Skip to content

Instantly share code, notes, and snippets.

@LoneDev6

LoneDev6/HashMapPrimitive.java

Last active January 12, 2022 15:46
Download ZIP

Revisions

  1. LoneDev6 revised this gist Jan 12, 2022. 1 changed file with 4 additions and 2 deletions.
    6 changes: 4 additions & 2 deletions HashMapPrimitive.java
    View file
    Original file line number Diff line number Diff line change
    @@ -921,12 +921,13 @@ final <T> T[] prepareArray(T[] a) {
    * @return supplied array
    */
    <T> T[] keysToArray(T[] a) {
    Object[] r = a;
    Node<K,V>[] tab;
    int idx = 0;
    if (size > 0 && (tab = table) != null) {
    for (Node<K,V> e : tab) {
    for (; e != null; e = e.next) {
    ((Object[]) a)[idx++] = e.key;
    r[idx++] = e.key;
    }
    }
    }
    @@ -943,12 +944,13 @@ <T> T[] keysToArray(T[] a) {
    * @return supplied array
    */
    <T> T[] valuesToArray(T[] a) {
    Object[] r = a;
    Node<K,V>[] tab;
    int idx = 0;
    if (size > 0 && (tab = table) != null) {
    for (Node<K,V> e : tab) {
    for (; e != null; e = e.next) {
    ((Object[]) a)[idx++] = e.value;
    r[idx++] = e.value;
    }
    }
    }
  2. LoneDev6 renamed this gist Jan 12, 2022. 1 changed file with 115 additions and 129 deletions.
    244 changes: 115 additions & 129 deletions HashMap.java → HashMapPrimitive.java
    View file
    Original file line number Diff line number Diff line change
    @@ -23,23 +23,26 @@
    * questions.
    */

    package java.util;
    package dev.lone.itemsadder.FontImages;

    import jdk.internal.access.SharedSecrets;

    import java.io.IOException;
    import java.io.InvalidObjectException;
    import java.io.Serializable;
    import java.lang.reflect.ParameterizedType;
    import java.lang.reflect.Type;
    import java.util.*;
    import java.util.function.BiConsumer;
    import java.util.function.BiFunction;
    import java.util.function.Consumer;
    import java.util.function.Function;
    import jdk.internal.access.SharedSecrets;

    /**
    * Works good only with native objects since it skips class checking completely.
    * This is a pure hack.
    *
    * Hash table based implementation of the {@code Map} interface. This
    * implementation provides all of the optional map operations, and permits
    * {@code null} values and the {@code null} key. (The {@code HashMap}
    * {@code null} values and the {@code null} key. (The {@code HashNative}
    * class is roughly equivalent to {@code Hashtable}, except that it is
    * unsynchronized and permits nulls.) This class makes no guarantees as to
    * the order of the map; in particular, it does not guarantee that the order
    @@ -49,12 +52,12 @@
    * operations ({@code get} and {@code put}), assuming the hash function
    * disperses the elements properly among the buckets. Iteration over
    * collection views requires time proportional to the "capacity" of the
    * {@code HashMap} instance (the number of buckets) plus its size (the number
    * {@code HashNative} instance (the number of buckets) plus its size (the number
    * of key-value mappings). Thus, it's very important not to set the initial
    * capacity too high (or the load factor too low) if iteration performance is
    * important.
    *
    * <p>An instance of {@code HashMap} has two parameters that affect its
    * <p>An instance of {@code HashNative} has two parameters that affect its
    * performance: <i>initial capacity</i> and <i>load factor</i>. The
    * <i>capacity</i> is the number of buckets in the hash table, and the initial
    * capacity is simply the capacity at the time the hash table is created. The
    @@ -68,15 +71,15 @@
    * <p>As a general rule, the default load factor (.75) offers a good
    * tradeoff between time and space costs. Higher values decrease the
    * space overhead but increase the lookup cost (reflected in most of
    * the operations of the {@code HashMap} class, including
    * the operations of the {@code HashNative} class, including
    * {@code get} and {@code put}). The expected number of entries in
    * the map and its load factor should be taken into account when
    * setting its initial capacity, so as to minimize the number of
    * rehash operations. If the initial capacity is greater than the
    * maximum number of entries divided by the load factor, no rehash
    * operations will ever occur.
    *
    * <p>If many mappings are to be stored in a {@code HashMap}
    * <p>If many mappings are to be stored in a {@code HashNative}
    * instance, creating it with a sufficiently large capacity will allow
    * the mappings to be stored more efficiently than letting it perform
    * automatic rehashing as needed to grow the table. Note that using
    @@ -98,7 +101,7 @@
    * {@link Collections#synchronizedMap Collections.synchronizedMap}
    * method. This is best done at creation time, to prevent accidental
    * unsynchronized access to the map:<pre>
    * Map m = Collections.synchronizedMap(new HashMap(...));</pre>
    * Map m = Collections.synchronizedMap(new HashNative(...));</pre>
    *
    * <p>The iterators returned by all of this class's "collection view methods"
    * are <i>fail-fast</i>: if the map is structurally modified at any time after
    @@ -135,10 +138,9 @@
    * @see Hashtable
    * @since 1.2
    */
    public class HashMap<K,V> extends AbstractMap<K,V>
    public class HashMapPrimitive<K,V> extends AbstractMap<K,V>
    implements Map<K,V>, Cloneable, Serializable {

    @java.io.Serial
    private static final long serialVersionUID = 362498820763181265L;

    /*
    @@ -220,9 +222,9 @@ public class HashMap<K,V> extends AbstractMap<K,V>
    * tie-breakers.
    *
    * The use and transitions among plain vs tree modes is
    * complicated by the existence of subclass LinkedHashMap. See
    * complicated by the existence of subclass LinkedHashNative. See
    * below for hook methods defined to be invoked upon insertion,
    * removal and access that allow LinkedHashMap internals to
    * removal and access that allow LinkedHashNative internals to
    * otherwise remain independent of these mechanics. (This also
    * requires that a map instance be passed to some utility methods
    * that may create new nodes.)
    @@ -275,7 +277,7 @@ public class HashMap<K,V> extends AbstractMap<K,V>

    /**
    * Basic hash bin node, used for most entries. (See below for
    * TreeNode subclass, and in LinkedHashMap for its Entry subclass.)
    * TreeNode subclass, and in LinkedHashNative for its Entry subclass.)
    */
    static class Node<K,V> implements Map.Entry<K,V> {
    final int hash;
    @@ -309,9 +311,8 @@ public final boolean equals(Object o) {
    return true;
    if (o instanceof Map.Entry) {
    Map.Entry<?,?> e = (Map.Entry<?,?>)o;
    if (Objects.equals(key, e.getKey()) &&
    Objects.equals(value, e.getValue()))
    return true;
    return Objects.equals(key, e.getKey()) &&
    Objects.equals(value, e.getValue());
    }
    return false;
    }
    @@ -340,37 +341,13 @@ static final int hash(Object key) {
    return (key == null) ? 0 : (h = key.hashCode()) ^ (h >>> 16);
    }

    /**
    * Returns x's Class if it is of the form "class C implements
    * Comparable<C>", else null.
    */
    static Class<?> comparableClassFor(Object x) {
    if (x instanceof Comparable) {
    Class<?> c; Type[] ts, as; ParameterizedType p;
    if ((c = x.getClass()) == String.class) // bypass checks
    return c;
    if ((ts = c.getGenericInterfaces()) != null) {
    for (Type t : ts) {
    if ((t instanceof ParameterizedType) &&
    ((p = (ParameterizedType) t).getRawType() ==
    Comparable.class) &&
    (as = p.getActualTypeArguments()) != null &&
    as.length == 1 && as[0] == c) // type arg is c
    return c;
    }
    }
    }
    return null;
    }

    /**
    * Returns k.compareTo(x) if x matches kc (k's screened comparable
    * class), else 0.
    */
    @SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
    static int compareComparables(Class<?> kc, Object k, Object x) {
    return (x == null || x.getClass() != kc ? 0 :
    ((Comparable)k).compareTo(x));
    static int compareComparables(Object k, Object x) {
    return (x == null ? 0 : ((Comparable)k).compareTo(x));
    }

    /**
    @@ -395,19 +372,19 @@ static final int tableSizeFor(int cap) {
    * Holds cached entrySet(). Note that AbstractMap fields are used
    * for keySet() and values().
    */
    transient Set<Map.Entry<K,V>> entrySet;
    transient Set<Entry<K,V>> entrySet;

    /**
    * The number of key-value mappings contained in this map.
    */
    transient int size;

    /**
    * The number of times this HashMap has been structurally modified
    * The number of times this HashNative has been structurally modified
    * Structural modifications are those that change the number of mappings in
    * the HashMap or otherwise modify its internal structure (e.g.,
    * the HashNative or otherwise modify its internal structure (e.g.,
    * rehash). This field is used to make iterators on Collection-views of
    * the HashMap fail-fast. (See ConcurrentModificationException).
    * the HashNative fail-fast. (See ConcurrentModificationException).
    */
    transient int modCount;

    @@ -432,15 +409,15 @@ static final int tableSizeFor(int cap) {
    /* ---------------- Public operations -------------- */

    /**
    * Constructs an empty {@code HashMap} with the specified initial
    * Constructs an empty {@code HashNative} with the specified initial
    * capacity and load factor.
    *
    * @param initialCapacity the initial capacity
    * @param loadFactor the load factor
    * @throws IllegalArgumentException if the initial capacity is negative
    * or the load factor is nonpositive
    */
    public HashMap(int initialCapacity, float loadFactor) {
    public HashMapPrimitive(int initialCapacity, float loadFactor) {
    if (initialCapacity < 0)
    throw new IllegalArgumentException("Illegal initial capacity: " +
    initialCapacity);
    @@ -454,34 +431,34 @@ public HashMap(int initialCapacity, float loadFactor) {
    }

    /**
    * Constructs an empty {@code HashMap} with the specified initial
    * Constructs an empty {@code HashNative} with the specified initial
    * capacity and the default load factor (0.75).
    *
    * @param initialCapacity the initial capacity.
    * @throws IllegalArgumentException if the initial capacity is negative.
    */
    public HashMap(int initialCapacity) {
    public HashMapPrimitive(int initialCapacity) {
    this(initialCapacity, DEFAULT_LOAD_FACTOR);
    }

    /**
    * Constructs an empty {@code HashMap} with the default initial capacity
    * Constructs an empty {@code HashNative} with the default initial capacity
    * (16) and the default load factor (0.75).
    */
    public HashMap() {
    public HashMapPrimitive() {
    this.loadFactor = DEFAULT_LOAD_FACTOR; // all other fields defaulted
    }

    /**
    * Constructs a new {@code HashMap} with the same mappings as the
    * specified {@code Map}. The {@code HashMap} is created with
    * Constructs a new {@code HashNative} with the same mappings as the
    * specified {@code Map}. The {@code HashNative} is created with
    * default load factor (0.75) and an initial capacity sufficient to
    * hold the mappings in the specified {@code Map}.
    *
    * @param m the map whose mappings are to be placed in this map
    * @throws NullPointerException if the specified map is null
    */
    public HashMap(Map<? extends K, ? extends V> m) {
    public HashMapPrimitive(Map<? extends K, ? extends V> m) {
    this.loadFactor = DEFAULT_LOAD_FACTOR;
    putMapEntries(m, false);
    }
    @@ -700,7 +677,7 @@ else if (oldThr > 0) // initial capacity was placed in threshold
    (int)ft : Integer.MAX_VALUE);
    }
    threshold = newThr;
    @SuppressWarnings({"rawtypes","unchecked"})
    @SuppressWarnings({"unchecked"})
    Node<K,V>[] newTab = (Node<K,V>[])new Node[newCap];
    table = newTab;
    if (oldTab != null) {
    @@ -903,12 +880,13 @@ public boolean containsValue(Object value) {
    * @return a set view of the keys contained in this map
    */
    public Set<K> keySet() {
    Set<K> ks = keySet;
    if (ks == null) {
    ks = new KeySet();
    keySet = ks;
    }
    return ks;
    // Set<K> ks = keySet;
    // if (ks == null) {
    // ks = new KeySet();
    // keySet = ks;
    // }
    // return ks;
    throw new RuntimeException("Not implemented!");
    }

    /**
    @@ -943,13 +921,12 @@ final <T> T[] prepareArray(T[] a) {
    * @return supplied array
    */
    <T> T[] keysToArray(T[] a) {
    Object[] r = a;
    Node<K,V>[] tab;
    int idx = 0;
    if (size > 0 && (tab = table) != null) {
    for (Node<K,V> e : tab) {
    for (; e != null; e = e.next) {
    r[idx++] = e.key;
    ((Object[]) a)[idx++] = e.key;
    }
    }
    }
    @@ -966,13 +943,12 @@ <T> T[] keysToArray(T[] a) {
    * @return supplied array
    */
    <T> T[] valuesToArray(T[] a) {
    Object[] r = a;
    Node<K,V>[] tab;
    int idx = 0;
    if (size > 0 && (tab = table) != null) {
    for (Node<K,V> e : tab) {
    for (; e != null; e = e.next) {
    r[idx++] = e.value;
    ((Object[]) a)[idx++] = e.value;
    }
    }
    }
    @@ -981,14 +957,14 @@ <T> T[] valuesToArray(T[] a) {

    final class KeySet extends AbstractSet<K> {
    public final int size() { return size; }
    public final void clear() { HashMap.this.clear(); }
    public final void clear() { HashMapPrimitive.this.clear(); }
    public final Iterator<K> iterator() { return new KeyIterator(); }
    public final boolean contains(Object o) { return containsKey(o); }
    public final boolean remove(Object key) {
    return removeNode(hash(key), key, null, false, true) != null;
    }
    public final Spliterator<K> spliterator() {
    return new KeySpliterator<>(HashMap.this, 0, -1, 0, 0);
    return new KeySpliterator<>(HashMapPrimitive.this, 0, -1, 0, 0);
    }

    public Object[] toArray() {
    @@ -1031,21 +1007,16 @@ public final void forEach(Consumer<? super K> action) {
    * @return a view of the values contained in this map
    */
    public Collection<V> values() {
    Collection<V> vs = values;
    if (vs == null) {
    vs = new Values();
    values = vs;
    }
    return vs;
    throw new RuntimeException("Not implemented!");
    }

    final class Values extends AbstractCollection<V> {
    public final int size() { return size; }
    public final void clear() { HashMap.this.clear(); }
    public final void clear() { HashMapPrimitive.this.clear(); }
    public final Iterator<V> iterator() { return new ValueIterator(); }
    public final boolean contains(Object o) { return containsValue(o); }
    public final Spliterator<V> spliterator() {
    return new ValueSpliterator<>(HashMap.this, 0, -1, 0, 0);
    return new ValueSpliterator<>(HashMapPrimitive.this, 0, -1, 0, 0);
    }

    public Object[] toArray() {
    @@ -1089,13 +1060,14 @@ public final void forEach(Consumer<? super V> action) {
    * @return a set view of the mappings contained in this map
    */
    public Set<Map.Entry<K,V>> entrySet() {
    Set<Map.Entry<K,V>> es;
    return (es = entrySet) == null ? (entrySet = new EntrySet()) : es;
    // Set<Map.Entry<K,V>> es;
    // return (es = entrySet) == null ? (entrySet = new EntrySet()) : es;
    throw new RuntimeException("Not implemented!");
    }

    final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
    public final int size() { return size; }
    public final void clear() { HashMap.this.clear(); }
    public final void clear() { HashMapPrimitive.this.clear(); }
    public final Iterator<Map.Entry<K,V>> iterator() {
    return new EntryIterator();
    }
    @@ -1117,7 +1089,7 @@ public final boolean remove(Object o) {
    return false;
    }
    public final Spliterator<Map.Entry<K,V>> spliterator() {
    return new EntrySpliterator<>(HashMap.this, 0, -1, 0, 0);
    return new EntrySpliterator<>(HashMapPrimitive.this, 0, -1, 0, 0);
    }
    public final void forEach(Consumer<? super Map.Entry<K,V>> action) {
    Node<K,V>[] tab;
    @@ -1450,17 +1422,17 @@ public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
    // Cloning and serialization

    /**
    * Returns a shallow copy of this {@code HashMap} instance: the keys and
    * Returns a shallow copy of this {@code HashNative} instance: the keys and
    * values themselves are not cloned.
    *
    * @return a shallow copy of this map
    */
    @SuppressWarnings("unchecked")
    @Override
    public Object clone() {
    HashMap<K,V> result;
    HashMapPrimitive<K,V> result;
    try {
    result = (HashMap<K,V>)super.clone();
    result = (HashMapPrimitive<K,V>)super.clone();
    } catch (CloneNotSupportedException e) {
    // this shouldn't happen, since we are Cloneable
    throw new InternalError(e);
    @@ -1483,14 +1455,14 @@ final int capacity() {
    *
    * @param s the stream
    * @throws IOException if an I/O error occurs
    * @serialData The <i>capacity</i> of the HashMap (the length of the
    * @serialData The <i>capacity</i> of the HashNative (the length of the
    * bucket array) is emitted (int), followed by the
    * <i>size</i> (an int, the number of key-value
    * mappings), followed by the key (Object) and value (Object)
    * for each key-value mapping. The key-value mappings are
    * emitted in no particular order.
    */
    @java.io.Serial
    // @java.io.Serial
    private void writeObject(java.io.ObjectOutputStream s)
    throws IOException {
    int buckets = capacity();
    @@ -1508,7 +1480,6 @@ private void writeObject(java.io.ObjectOutputStream s)
    * could not be found
    * @throws IOException if an I/O error occurs
    */
    @java.io.Serial
    private void readObject(java.io.ObjectInputStream s)
    throws IOException, ClassNotFoundException {
    // Read in the threshold (ignored), loadfactor, and any hidden stuff
    @@ -1539,11 +1510,11 @@ else if (mappings > 0) { // (if zero, use defaults)
    // Check Map.Entry[].class since it's the nearest public type to
    // what we're actually creating.
    SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Map.Entry[].class, cap);
    @SuppressWarnings({"rawtypes","unchecked"})
    @SuppressWarnings({"unchecked"})
    Node<K,V>[] tab = (Node<K,V>[])new Node[cap];
    table = tab;

    // Read the keys and values, and put the mappings in the HashMap
    // Read the keys and values, and put the mappings in the HashNative
    for (int i = 0; i < mappings; i++) {
    @SuppressWarnings("unchecked")
    K key = (K) s.readObject();
    @@ -1620,17 +1591,17 @@ final class EntryIterator extends HashIterator
    /* ------------------------------------------------------------ */
    // spliterators

    static class HashMapSpliterator<K,V> {
    final HashMap<K,V> map;
    static class HashNativeSpliterator<K,V> {
    final HashMapPrimitive<K,V> map;
    Node<K,V> current; // current node
    int index; // current index, modified on advance/split
    int fence; // one past last index
    int est; // size estimate
    int expectedModCount; // for comodification checks

    HashMapSpliterator(HashMap<K,V> m, int origin,
    int fence, int est,
    int expectedModCount) {
    HashNativeSpliterator(HashMapPrimitive<K,V> m, int origin,
    int fence, int est,
    int expectedModCount) {
    this.map = m;
    this.index = origin;
    this.fence = fence;
    @@ -1641,7 +1612,7 @@ static class HashMapSpliterator<K,V> {
    final int getFence() { // initialize fence and size on first use
    int hi;
    if ((hi = fence) < 0) {
    HashMap<K,V> m = map;
    HashMapPrimitive<K,V> m = map;
    est = m.size;
    expectedModCount = m.modCount;
    Node<K,V>[] tab = m.table;
    @@ -1652,14 +1623,14 @@ final int getFence() { // initialize fence and size on first use

    public final long estimateSize() {
    getFence(); // force init
    return (long) est;
    return est;
    }
    }

    static final class KeySpliterator<K,V>
    extends HashMapSpliterator<K,V>
    extends HashNativeSpliterator<K,V>
    implements Spliterator<K> {
    KeySpliterator(HashMap<K,V> m, int origin, int fence, int est,
    KeySpliterator(HashMapPrimitive<K,V> m, int origin, int fence, int est,
    int expectedModCount) {
    super(m, origin, fence, est, expectedModCount);
    }
    @@ -1675,7 +1646,7 @@ public void forEachRemaining(Consumer<? super K> action) {
    int i, hi, mc;
    if (action == null)
    throw new NullPointerException();
    HashMap<K,V> m = map;
    HashMapPrimitive<K,V> m = map;
    Node<K,V>[] tab = m.table;
    if ((hi = fence) < 0) {
    mc = expectedModCount = m.modCount;
    @@ -1729,9 +1700,9 @@ public int characteristics() {
    }

    static final class ValueSpliterator<K,V>
    extends HashMapSpliterator<K,V>
    extends HashNativeSpliterator<K,V>
    implements Spliterator<V> {
    ValueSpliterator(HashMap<K,V> m, int origin, int fence, int est,
    ValueSpliterator(HashMapPrimitive<K,V> m, int origin, int fence, int est,
    int expectedModCount) {
    super(m, origin, fence, est, expectedModCount);
    }
    @@ -1747,7 +1718,7 @@ public void forEachRemaining(Consumer<? super V> action) {
    int i, hi, mc;
    if (action == null)
    throw new NullPointerException();
    HashMap<K,V> m = map;
    HashMapPrimitive<K,V> m = map;
    Node<K,V>[] tab = m.table;
    if ((hi = fence) < 0) {
    mc = expectedModCount = m.modCount;
    @@ -1800,9 +1771,9 @@ public int characteristics() {
    }

    static final class EntrySpliterator<K,V>
    extends HashMapSpliterator<K,V>
    extends HashNativeSpliterator<K,V>
    implements Spliterator<Map.Entry<K,V>> {
    EntrySpliterator(HashMap<K,V> m, int origin, int fence, int est,
    EntrySpliterator(HashMapPrimitive<K,V> m, int origin, int fence, int est,
    int expectedModCount) {
    super(m, origin, fence, est, expectedModCount);
    }
    @@ -1818,7 +1789,7 @@ public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
    int i, hi, mc;
    if (action == null)
    throw new NullPointerException();
    HashMap<K,V> m = map;
    HashMapPrimitive<K,V> m = map;
    Node<K,V>[] tab = m.table;
    if ((hi = fence) < 0) {
    mc = expectedModCount = m.modCount;
    @@ -1872,14 +1843,14 @@ public int characteristics() {
    }

    /* ------------------------------------------------------------ */
    // LinkedHashMap support
    // LinkedHashNative support


    /*
    * The following package-protected methods are designed to be
    * overridden by LinkedHashMap, but not by any other subclass.
    * overridden by LinkedHashNative, but not by any other subclass.
    * Nearly all other internal methods are also package-protected
    * but are declared final, so can be used by LinkedHashMap, view
    * but are declared final, so can be used by LinkedHashNative, view
    * classes, and HashSet.
    */

    @@ -1907,16 +1878,18 @@ TreeNode<K,V> replacementTreeNode(Node<K,V> p, Node<K,V> next) {
    * Reset to initial default state. Called by clone and readObject.
    */
    void reinitialize() {
    table = null;
    entrySet = null;
    keySet = null;
    values = null;
    modCount = 0;
    threshold = 0;
    size = 0;
    // table = null;
    // entrySet = null;
    // keySet = null;
    // values = null;
    // super.values().clear(); // bad?
    // modCount = 0;
    // threshold = 0;
    // size = 0;
    throw new RuntimeException("Not implemented!");
    }

    // Callbacks to allow LinkedHashMap post-actions
    // Callbacks to allow LinkedHashNative post-actions
    void afterNodeAccess(Node<K,V> p) { }
    void afterNodeInsertion(boolean evict) { }
    void afterNodeRemoval(Node<K,V> p) { }
    @@ -1938,11 +1911,21 @@ void internalWriteEntries(java.io.ObjectOutputStream s) throws IOException {
    // Tree bins

    /**
    * Entry for Tree bins. Extends LinkedHashMap.Entry (which in turn
    * HashNative.Node subclass for normal LinkedHashNative entries.
    */
    static class Entry<K,V> extends Node<K,V> {
    Entry<K,V> before, after;
    Entry(int hash, K key, V value, Node<K,V> next) {
    super(hash, key, value, next);
    }
    }

    /**
    * Entry for Tree bins. Extends Entry (which in turn
    * extends Node) so can be used as extension of either regular or
    * linked node.
    */
    static final class TreeNode<K,V> extends LinkedHashMap.Entry<K,V> {
    static final class TreeNode<K,V> extends Entry<K,V> {
    TreeNode<K,V> parent; // red-black tree links
    TreeNode<K,V> left;
    TreeNode<K,V> right;
    @@ -2009,8 +1992,9 @@ else if (pl == null)
    else if (pr == null)
    p = pl;
    else if ((kc != null ||
    (kc = comparableClassFor(k)) != null) &&
    (dir = compareComparables(kc, k, pk)) != 0)
    //(kc = comparableClassFor(k)) != null) &&
    (kc = k != null ? k.getClass() : null) != null) &&
    (dir = compareComparables(k, pk)) != 0)
    p = (dir < 0) ? pl : pr;
    else if ((q = pr.find(h, k, kc)) != null)
    return q;
    @@ -2069,8 +2053,9 @@ final void treeify(Node<K,V>[] tab) {
    else if (ph < h)
    dir = 1;
    else if ((kc == null &&
    (kc = comparableClassFor(k)) == null) ||
    (dir = compareComparables(kc, k, pk)) == 0)
    // (kc = comparableClassFor(k)) == null) ||
    (kc = k.getClass()) == null) ||
    (dir = compareComparables(k, pk)) == 0)
    dir = tieBreakOrder(k, pk);

    TreeNode<K,V> xp = p;
    @@ -2093,7 +2078,7 @@ else if ((kc == null &&
    * Returns a list of non-TreeNodes replacing those linked from
    * this node.
    */
    final Node<K,V> untreeify(HashMap<K,V> map) {
    final Node<K,V> untreeify(HashMapPrimitive<K,V> map) {
    Node<K,V> hd = null, tl = null;
    for (Node<K,V> q = this; q != null; q = q.next) {
    Node<K,V> p = map.replacementNode(q, null);
    @@ -2109,7 +2094,7 @@ final Node<K,V> untreeify(HashMap<K,V> map) {
    /**
    * Tree version of putVal.
    */
    final TreeNode<K,V> putTreeVal(HashMap<K,V> map, Node<K,V>[] tab,
    final TreeNode<K,V> putTreeVal(HashMapPrimitive<K,V> map, Node<K,V>[] tab,
    int h, K k, V v) {
    Class<?> kc = null;
    boolean searched = false;
    @@ -2123,8 +2108,9 @@ else if (ph < h)
    else if ((pk = p.key) == k || (k != null && k.equals(pk)))
    return p;
    else if ((kc == null &&
    (kc = comparableClassFor(k)) == null) ||
    (dir = compareComparables(kc, k, pk)) == 0) {
    // (kc = comparableClassFor(k)) == null) ||
    (kc = k.getClass()) == null) ||
    (dir = compareComparables(k, pk)) == 0) {
    if (!searched) {
    TreeNode<K,V> q, ch;
    searched = true;
    @@ -2165,7 +2151,7 @@ else if ((kc == null &&
    * the bin is converted back to a plain bin. (The test triggers
    * somewhere between 2 and 6 nodes, depending on tree structure).
    */
    final void removeTreeNode(HashMap<K,V> map, Node<K,V>[] tab,
    final void removeTreeNode(HashMapPrimitive<K,V> map, Node<K,V>[] tab,
    boolean movable) {
    int n;
    if (tab == null || (n = tab.length) == 0)
    @@ -2273,7 +2259,7 @@ else if (p == pp.right)
    * @param index the index of the table being split
    * @param bit the bit of hash to split on
    */
    final void split(HashMap<K,V> map, Node<K,V>[] tab, int index, int bit) {
    final void split(HashMapPrimitive<K,V> map, Node<K,V>[] tab, int index, int bit) {
    TreeNode<K,V> b = this;
    // Relink into lo and hi lists, preserving order
    TreeNode<K,V> loHead = null, loTail = null;
  3. LoneDev6 created this gist Jan 12, 2022.
    2,535 changes: 2,535 additions & 0 deletions HashMap.java
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,2535 @@
    /*
    * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    *
    * This code is free software; you can redistribute it and/or modify it
    * under the terms of the GNU General Public License version 2 only, as
    * published by the Free Software Foundation. Oracle designates this
    * particular file as subject to the "Classpath" exception as provided
    * by Oracle in the LICENSE file that accompanied this code.
    *
    * This code is distributed in the hope that it will be useful, but WITHOUT
    * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
    * version 2 for more details (a copy is included in the LICENSE file that
    * accompanied this code).
    *
    * You should have received a copy of the GNU General Public License version
    * 2 along with this work; if not, write to the Free Software Foundation,
    * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    *
    * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    * or visit www.oracle.com if you need additional information or have any
    * questions.
    */

    package java.util;

    import java.io.IOException;
    import java.io.InvalidObjectException;
    import java.io.Serializable;
    import java.lang.reflect.ParameterizedType;
    import java.lang.reflect.Type;
    import java.util.function.BiConsumer;
    import java.util.function.BiFunction;
    import java.util.function.Consumer;
    import java.util.function.Function;
    import jdk.internal.access.SharedSecrets;

    /**
    * Hash table based implementation of the {@code Map} interface. This
    * implementation provides all of the optional map operations, and permits
    * {@code null} values and the {@code null} key. (The {@code HashMap}
    * class is roughly equivalent to {@code Hashtable}, except that it is
    * unsynchronized and permits nulls.) This class makes no guarantees as to
    * the order of the map; in particular, it does not guarantee that the order
    * will remain constant over time.
    *
    * <p>This implementation provides constant-time performance for the basic
    * operations ({@code get} and {@code put}), assuming the hash function
    * disperses the elements properly among the buckets. Iteration over
    * collection views requires time proportional to the "capacity" of the
    * {@code HashMap} instance (the number of buckets) plus its size (the number
    * of key-value mappings). Thus, it's very important not to set the initial
    * capacity too high (or the load factor too low) if iteration performance is
    * important.
    *
    * <p>An instance of {@code HashMap} has two parameters that affect its
    * performance: <i>initial capacity</i> and <i>load factor</i>. The
    * <i>capacity</i> is the number of buckets in the hash table, and the initial
    * capacity is simply the capacity at the time the hash table is created. The
    * <i>load factor</i> is a measure of how full the hash table is allowed to
    * get before its capacity is automatically increased. When the number of
    * entries in the hash table exceeds the product of the load factor and the
    * current capacity, the hash table is <i>rehashed</i> (that is, internal data
    * structures are rebuilt) so that the hash table has approximately twice the
    * number of buckets.
    *
    * <p>As a general rule, the default load factor (.75) offers a good
    * tradeoff between time and space costs. Higher values decrease the
    * space overhead but increase the lookup cost (reflected in most of
    * the operations of the {@code HashMap} class, including
    * {@code get} and {@code put}). The expected number of entries in
    * the map and its load factor should be taken into account when
    * setting its initial capacity, so as to minimize the number of
    * rehash operations. If the initial capacity is greater than the
    * maximum number of entries divided by the load factor, no rehash
    * operations will ever occur.
    *
    * <p>If many mappings are to be stored in a {@code HashMap}
    * instance, creating it with a sufficiently large capacity will allow
    * the mappings to be stored more efficiently than letting it perform
    * automatic rehashing as needed to grow the table. Note that using
    * many keys with the same {@code hashCode()} is a sure way to slow
    * down performance of any hash table. To ameliorate impact, when keys
    * are {@link Comparable}, this class may use comparison order among
    * keys to help break ties.
    *
    * <p><strong>Note that this implementation is not synchronized.</strong>
    * If multiple threads access a hash map concurrently, and at least one of
    * the threads modifies the map structurally, it <i>must</i> be
    * synchronized externally. (A structural modification is any operation
    * that adds or deletes one or more mappings; merely changing the value
    * associated with a key that an instance already contains is not a
    * structural modification.) This is typically accomplished by
    * synchronizing on some object that naturally encapsulates the map.
    *
    * If no such object exists, the map should be "wrapped" using the
    * {@link Collections#synchronizedMap Collections.synchronizedMap}
    * method. This is best done at creation time, to prevent accidental
    * unsynchronized access to the map:<pre>
    * Map m = Collections.synchronizedMap(new HashMap(...));</pre>
    *
    * <p>The iterators returned by all of this class's "collection view methods"
    * are <i>fail-fast</i>: if the map is structurally modified at any time after
    * the iterator is created, in any way except through the iterator's own
    * {@code remove} method, the iterator will throw a
    * {@link ConcurrentModificationException}. Thus, in the face of concurrent
    * modification, the iterator fails quickly and cleanly, rather than risking
    * arbitrary, non-deterministic behavior at an undetermined time in the
    * future.
    *
    * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
    * as it is, generally speaking, impossible to make any hard guarantees in the
    * presence of unsynchronized concurrent modification. Fail-fast iterators
    * throw {@code ConcurrentModificationException} on a best-effort basis.
    * Therefore, it would be wrong to write a program that depended on this
    * exception for its correctness: <i>the fail-fast behavior of iterators
    * should be used only to detect bugs.</i>
    *
    * <p>This class is a member of the
    * <a href="{@docRoot}/java.base/java/util/package-summary.html#CollectionsFramework">
    * Java Collections Framework</a>.
    *
    * @param <K> the type of keys maintained by this map
    * @param <V> the type of mapped values
    *
    * @author Doug Lea
    * @author Josh Bloch
    * @author Arthur van Hoff
    * @author Neal Gafter
    * @see Object#hashCode()
    * @see Collection
    * @see Map
    * @see TreeMap
    * @see Hashtable
    * @since 1.2
    */
    public class HashMap<K,V> extends AbstractMap<K,V>
    implements Map<K,V>, Cloneable, Serializable {

    @java.io.Serial
    private static final long serialVersionUID = 362498820763181265L;

    /*
    * Implementation notes.
    *
    * This map usually acts as a binned (bucketed) hash table, but
    * when bins get too large, they are transformed into bins of
    * TreeNodes, each structured similarly to those in
    * java.util.TreeMap. Most methods try to use normal bins, but
    * relay to TreeNode methods when applicable (simply by checking
    * instanceof a node). Bins of TreeNodes may be traversed and
    * used like any others, but additionally support faster lookup
    * when overpopulated. However, since the vast majority of bins in
    * normal use are not overpopulated, checking for existence of
    * tree bins may be delayed in the course of table methods.
    *
    * Tree bins (i.e., bins whose elements are all TreeNodes) are
    * ordered primarily by hashCode, but in the case of ties, if two
    * elements are of the same "class C implements Comparable<C>",
    * type then their compareTo method is used for ordering. (We
    * conservatively check generic types via reflection to validate
    * this -- see method comparableClassFor). The added complexity
    * of tree bins is worthwhile in providing worst-case O(log n)
    * operations when keys either have distinct hashes or are
    * orderable, Thus, performance degrades gracefully under
    * accidental or malicious usages in which hashCode() methods
    * return values that are poorly distributed, as well as those in
    * which many keys share a hashCode, so long as they are also
    * Comparable. (If neither of these apply, we may waste about a
    * factor of two in time and space compared to taking no
    * precautions. But the only known cases stem from poor user
    * programming practices that are already so slow that this makes
    * little difference.)
    *
    * Because TreeNodes are about twice the size of regular nodes, we
    * use them only when bins contain enough nodes to warrant use
    * (see TREEIFY_THRESHOLD). And when they become too small (due to
    * removal or resizing) they are converted back to plain bins. In
    * usages with well-distributed user hashCodes, tree bins are
    * rarely used. Ideally, under random hashCodes, the frequency of
    * nodes in bins follows a Poisson distribution
    * (http://en.wikipedia.org/wiki/Poisson_distribution) with a
    * parameter of about 0.5 on average for the default resizing
    * threshold of 0.75, although with a large variance because of
    * resizing granularity. Ignoring variance, the expected
    * occurrences of list size k are (exp(-0.5) * pow(0.5, k) /
    * factorial(k)). The first values are:
    *
    * 0: 0.60653066
    * 1: 0.30326533
    * 2: 0.07581633
    * 3: 0.01263606
    * 4: 0.00157952
    * 5: 0.00015795
    * 6: 0.00001316
    * 7: 0.00000094
    * 8: 0.00000006
    * more: less than 1 in ten million
    *
    * The root of a tree bin is normally its first node. However,
    * sometimes (currently only upon Iterator.remove), the root might
    * be elsewhere, but can be recovered following parent links
    * (method TreeNode.root()).
    *
    * All applicable internal methods accept a hash code as an
    * argument (as normally supplied from a public method), allowing
    * them to call each other without recomputing user hashCodes.
    * Most internal methods also accept a "tab" argument, that is
    * normally the current table, but may be a new or old one when
    * resizing or converting.
    *
    * When bin lists are treeified, split, or untreeified, we keep
    * them in the same relative access/traversal order (i.e., field
    * Node.next) to better preserve locality, and to slightly
    * simplify handling of splits and traversals that invoke
    * iterator.remove. When using comparators on insertion, to keep a
    * total ordering (or as close as is required here) across
    * rebalancings, we compare classes and identityHashCodes as
    * tie-breakers.
    *
    * The use and transitions among plain vs tree modes is
    * complicated by the existence of subclass LinkedHashMap. See
    * below for hook methods defined to be invoked upon insertion,
    * removal and access that allow LinkedHashMap internals to
    * otherwise remain independent of these mechanics. (This also
    * requires that a map instance be passed to some utility methods
    * that may create new nodes.)
    *
    * The concurrent-programming-like SSA-based coding style helps
    * avoid aliasing errors amid all of the twisty pointer operations.
    */

    /**
    * The default initial capacity - MUST be a power of two.
    */
    static final int DEFAULT_INITIAL_CAPACITY = 1 << 4; // aka 16

    /**
    * The maximum capacity, used if a higher value is implicitly specified
    * by either of the constructors with arguments.
    * MUST be a power of two <= 1<<30.
    */
    static final int MAXIMUM_CAPACITY = 1 << 30;

    /**
    * The load factor used when none specified in constructor.
    */
    static final float DEFAULT_LOAD_FACTOR = 0.75f;

    /**
    * The bin count threshold for using a tree rather than list for a
    * bin. Bins are converted to trees when adding an element to a
    * bin with at least this many nodes. The value must be greater
    * than 2 and should be at least 8 to mesh with assumptions in
    * tree removal about conversion back to plain bins upon
    * shrinkage.
    */
    static final int TREEIFY_THRESHOLD = 8;

    /**
    * The bin count threshold for untreeifying a (split) bin during a
    * resize operation. Should be less than TREEIFY_THRESHOLD, and at
    * most 6 to mesh with shrinkage detection under removal.
    */
    static final int UNTREEIFY_THRESHOLD = 6;

    /**
    * The smallest table capacity for which bins may be treeified.
    * (Otherwise the table is resized if too many nodes in a bin.)
    * Should be at least 4 * TREEIFY_THRESHOLD to avoid conflicts
    * between resizing and treeification thresholds.
    */
    static final int MIN_TREEIFY_CAPACITY = 64;

    /**
    * Basic hash bin node, used for most entries. (See below for
    * TreeNode subclass, and in LinkedHashMap for its Entry subclass.)
    */
    static class Node<K,V> implements Map.Entry<K,V> {
    final int hash;
    final K key;
    V value;
    Node<K,V> next;

    Node(int hash, K key, V value, Node<K,V> next) {
    this.hash = hash;
    this.key = key;
    this.value = value;
    this.next = next;
    }

    public final K getKey() { return key; }
    public final V getValue() { return value; }
    public final String toString() { return key + "=" + value; }

    public final int hashCode() {
    return Objects.hashCode(key) ^ Objects.hashCode(value);
    }

    public final V setValue(V newValue) {
    V oldValue = value;
    value = newValue;
    return oldValue;
    }

    public final boolean equals(Object o) {
    if (o == this)
    return true;
    if (o instanceof Map.Entry) {
    Map.Entry<?,?> e = (Map.Entry<?,?>)o;
    if (Objects.equals(key, e.getKey()) &&
    Objects.equals(value, e.getValue()))
    return true;
    }
    return false;
    }
    }

    /* ---------------- Static utilities -------------- */

    /**
    * Computes key.hashCode() and spreads (XORs) higher bits of hash
    * to lower. Because the table uses power-of-two masking, sets of
    * hashes that vary only in bits above the current mask will
    * always collide. (Among known examples are sets of Float keys
    * holding consecutive whole numbers in small tables.) So we
    * apply a transform that spreads the impact of higher bits
    * downward. There is a tradeoff between speed, utility, and
    * quality of bit-spreading. Because many common sets of hashes
    * are already reasonably distributed (so don't benefit from
    * spreading), and because we use trees to handle large sets of
    * collisions in bins, we just XOR some shifted bits in the
    * cheapest possible way to reduce systematic lossage, as well as
    * to incorporate impact of the highest bits that would otherwise
    * never be used in index calculations because of table bounds.
    */
    static final int hash(Object key) {
    int h;
    return (key == null) ? 0 : (h = key.hashCode()) ^ (h >>> 16);
    }

    /**
    * Returns x's Class if it is of the form "class C implements
    * Comparable<C>", else null.
    */
    static Class<?> comparableClassFor(Object x) {
    if (x instanceof Comparable) {
    Class<?> c; Type[] ts, as; ParameterizedType p;
    if ((c = x.getClass()) == String.class) // bypass checks
    return c;
    if ((ts = c.getGenericInterfaces()) != null) {
    for (Type t : ts) {
    if ((t instanceof ParameterizedType) &&
    ((p = (ParameterizedType) t).getRawType() ==
    Comparable.class) &&
    (as = p.getActualTypeArguments()) != null &&
    as.length == 1 && as[0] == c) // type arg is c
    return c;
    }
    }
    }
    return null;
    }

    /**
    * Returns k.compareTo(x) if x matches kc (k's screened comparable
    * class), else 0.
    */
    @SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
    static int compareComparables(Class<?> kc, Object k, Object x) {
    return (x == null || x.getClass() != kc ? 0 :
    ((Comparable)k).compareTo(x));
    }

    /**
    * Returns a power of two size for the given target capacity.
    */
    static final int tableSizeFor(int cap) {
    int n = -1 >>> Integer.numberOfLeadingZeros(cap - 1);
    return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
    }

    /* ---------------- Fields -------------- */

    /**
    * The table, initialized on first use, and resized as
    * necessary. When allocated, length is always a power of two.
    * (We also tolerate length zero in some operations to allow
    * bootstrapping mechanics that are currently not needed.)
    */
    transient Node<K,V>[] table;

    /**
    * Holds cached entrySet(). Note that AbstractMap fields are used
    * for keySet() and values().
    */
    transient Set<Map.Entry<K,V>> entrySet;

    /**
    * The number of key-value mappings contained in this map.
    */
    transient int size;

    /**
    * The number of times this HashMap has been structurally modified
    * Structural modifications are those that change the number of mappings in
    * the HashMap or otherwise modify its internal structure (e.g.,
    * rehash). This field is used to make iterators on Collection-views of
    * the HashMap fail-fast. (See ConcurrentModificationException).
    */
    transient int modCount;

    /**
    * The next size value at which to resize (capacity * load factor).
    *
    * @serial
    */
    // (The javadoc description is true upon serialization.
    // Additionally, if the table array has not been allocated, this
    // field holds the initial array capacity, or zero signifying
    // DEFAULT_INITIAL_CAPACITY.)
    int threshold;

    /**
    * The load factor for the hash table.
    *
    * @serial
    */
    final float loadFactor;

    /* ---------------- Public operations -------------- */

    /**
    * Constructs an empty {@code HashMap} with the specified initial
    * capacity and load factor.
    *
    * @param initialCapacity the initial capacity
    * @param loadFactor the load factor
    * @throws IllegalArgumentException if the initial capacity is negative
    * or the load factor is nonpositive
    */
    public HashMap(int initialCapacity, float loadFactor) {
    if (initialCapacity < 0)
    throw new IllegalArgumentException("Illegal initial capacity: " +
    initialCapacity);
    if (initialCapacity > MAXIMUM_CAPACITY)
    initialCapacity = MAXIMUM_CAPACITY;
    if (loadFactor <= 0 || Float.isNaN(loadFactor))
    throw new IllegalArgumentException("Illegal load factor: " +
    loadFactor);
    this.loadFactor = loadFactor;
    this.threshold = tableSizeFor(initialCapacity);
    }

    /**
    * Constructs an empty {@code HashMap} with the specified initial
    * capacity and the default load factor (0.75).
    *
    * @param initialCapacity the initial capacity.
    * @throws IllegalArgumentException if the initial capacity is negative.
    */
    public HashMap(int initialCapacity) {
    this(initialCapacity, DEFAULT_LOAD_FACTOR);
    }

    /**
    * Constructs an empty {@code HashMap} with the default initial capacity
    * (16) and the default load factor (0.75).
    */
    public HashMap() {
    this.loadFactor = DEFAULT_LOAD_FACTOR; // all other fields defaulted
    }

    /**
    * Constructs a new {@code HashMap} with the same mappings as the
    * specified {@code Map}. The {@code HashMap} is created with
    * default load factor (0.75) and an initial capacity sufficient to
    * hold the mappings in the specified {@code Map}.
    *
    * @param m the map whose mappings are to be placed in this map
    * @throws NullPointerException if the specified map is null
    */
    public HashMap(Map<? extends K, ? extends V> m) {
    this.loadFactor = DEFAULT_LOAD_FACTOR;
    putMapEntries(m, false);
    }

    /**
    * Implements Map.putAll and Map constructor.
    *
    * @param m the map
    * @param evict false when initially constructing this map, else
    * true (relayed to method afterNodeInsertion).
    */
    final void putMapEntries(Map<? extends K, ? extends V> m, boolean evict) {
    int s = m.size();
    if (s > 0) {
    if (table == null) { // pre-size
    float ft = ((float)s / loadFactor) + 1.0F;
    int t = ((ft < (float)MAXIMUM_CAPACITY) ?
    (int)ft : MAXIMUM_CAPACITY);
    if (t > threshold)
    threshold = tableSizeFor(t);
    } else {
    // Because of linked-list bucket constraints, we cannot
    // expand all at once, but can reduce total resize
    // effort by repeated doubling now vs later
    while (s > threshold && table.length < MAXIMUM_CAPACITY)
    resize();
    }

    for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
    K key = e.getKey();
    V value = e.getValue();
    putVal(hash(key), key, value, false, evict);
    }
    }
    }

    /**
    * Returns the number of key-value mappings in this map.
    *
    * @return the number of key-value mappings in this map
    */
    public int size() {
    return size;
    }

    /**
    * Returns {@code true} if this map contains no key-value mappings.
    *
    * @return {@code true} if this map contains no key-value mappings
    */
    public boolean isEmpty() {
    return size == 0;
    }

    /**
    * Returns the value to which the specified key is mapped,
    * or {@code null} if this map contains no mapping for the key.
    *
    * <p>More formally, if this map contains a mapping from a key
    * {@code k} to a value {@code v} such that {@code (key==null ? k==null :
    * key.equals(k))}, then this method returns {@code v}; otherwise
    * it returns {@code null}. (There can be at most one such mapping.)
    *
    * <p>A return value of {@code null} does not <i>necessarily</i>
    * indicate that the map contains no mapping for the key; it's also
    * possible that the map explicitly maps the key to {@code null}.
    * The {@link #containsKey containsKey} operation may be used to
    * distinguish these two cases.
    *
    * @see #put(Object, Object)
    */
    public V get(Object key) {
    Node<K,V> e;
    return (e = getNode(key)) == null ? null : e.value;
    }

    /**
    * Implements Map.get and related methods.
    *
    * @param key the key
    * @return the node, or null if none
    */
    final Node<K,V> getNode(Object key) {
    Node<K,V>[] tab; Node<K,V> first, e; int n, hash; K k;
    if ((tab = table) != null && (n = tab.length) > 0 &&
    (first = tab[(n - 1) & (hash = hash(key))]) != null) {
    if (first.hash == hash && // always check first node
    ((k = first.key) == key || (key != null && key.equals(k))))
    return first;
    if ((e = first.next) != null) {
    if (first instanceof TreeNode)
    return ((TreeNode<K,V>)first).getTreeNode(hash, key);
    do {
    if (e.hash == hash &&
    ((k = e.key) == key || (key != null && key.equals(k))))
    return e;
    } while ((e = e.next) != null);
    }
    }
    return null;
    }

    /**
    * Returns {@code true} if this map contains a mapping for the
    * specified key.
    *
    * @param key The key whose presence in this map is to be tested
    * @return {@code true} if this map contains a mapping for the specified
    * key.
    */
    public boolean containsKey(Object key) {
    return getNode(key) != null;
    }

    /**
    * Associates the specified value with the specified key in this map.
    * If the map previously contained a mapping for the key, the old
    * value is replaced.
    *
    * @param key key with which the specified value is to be associated
    * @param value value to be associated with the specified key
    * @return the previous value associated with {@code key}, or
    * {@code null} if there was no mapping for {@code key}.
    * (A {@code null} return can also indicate that the map
    * previously associated {@code null} with {@code key}.)
    */
    public V put(K key, V value) {
    return putVal(hash(key), key, value, false, true);
    }

    /**
    * Implements Map.put and related methods.
    *
    * @param hash hash for key
    * @param key the key
    * @param value the value to put
    * @param onlyIfAbsent if true, don't change existing value
    * @param evict if false, the table is in creation mode.
    * @return previous value, or null if none
    */
    final V putVal(int hash, K key, V value, boolean onlyIfAbsent,
    boolean evict) {
    Node<K,V>[] tab; Node<K,V> p; int n, i;
    if ((tab = table) == null || (n = tab.length) == 0)
    n = (tab = resize()).length;
    if ((p = tab[i = (n - 1) & hash]) == null)
    tab[i] = newNode(hash, key, value, null);
    else {
    Node<K,V> e; K k;
    if (p.hash == hash &&
    ((k = p.key) == key || (key != null && key.equals(k))))
    e = p;
    else if (p instanceof TreeNode)
    e = ((TreeNode<K,V>)p).putTreeVal(this, tab, hash, key, value);
    else {
    for (int binCount = 0; ; ++binCount) {
    if ((e = p.next) == null) {
    p.next = newNode(hash, key, value, null);
    if (binCount >= TREEIFY_THRESHOLD - 1) // -1 for 1st
    treeifyBin(tab, hash);
    break;
    }
    if (e.hash == hash &&
    ((k = e.key) == key || (key != null && key.equals(k))))
    break;
    p = e;
    }
    }
    if (e != null) { // existing mapping for key
    V oldValue = e.value;
    if (!onlyIfAbsent || oldValue == null)
    e.value = value;
    afterNodeAccess(e);
    return oldValue;
    }
    }
    ++modCount;
    if (++size > threshold)
    resize();
    afterNodeInsertion(evict);
    return null;
    }

    /**
    * Initializes or doubles table size. If null, allocates in
    * accord with initial capacity target held in field threshold.
    * Otherwise, because we are using power-of-two expansion, the
    * elements from each bin must either stay at same index, or move
    * with a power of two offset in the new table.
    *
    * @return the table
    */
    final Node<K,V>[] resize() {
    Node<K,V>[] oldTab = table;
    int oldCap = (oldTab == null) ? 0 : oldTab.length;
    int oldThr = threshold;
    int newCap, newThr = 0;
    if (oldCap > 0) {
    if (oldCap >= MAXIMUM_CAPACITY) {
    threshold = Integer.MAX_VALUE;
    return oldTab;
    }
    else if ((newCap = oldCap << 1) < MAXIMUM_CAPACITY &&
    oldCap >= DEFAULT_INITIAL_CAPACITY)
    newThr = oldThr << 1; // double threshold
    }
    else if (oldThr > 0) // initial capacity was placed in threshold
    newCap = oldThr;
    else { // zero initial threshold signifies using defaults
    newCap = DEFAULT_INITIAL_CAPACITY;
    newThr = (int)(DEFAULT_LOAD_FACTOR * DEFAULT_INITIAL_CAPACITY);
    }
    if (newThr == 0) {
    float ft = (float)newCap * loadFactor;
    newThr = (newCap < MAXIMUM_CAPACITY && ft < (float)MAXIMUM_CAPACITY ?
    (int)ft : Integer.MAX_VALUE);
    }
    threshold = newThr;
    @SuppressWarnings({"rawtypes","unchecked"})
    Node<K,V>[] newTab = (Node<K,V>[])new Node[newCap];
    table = newTab;
    if (oldTab != null) {
    for (int j = 0; j < oldCap; ++j) {
    Node<K,V> e;
    if ((e = oldTab[j]) != null) {
    oldTab[j] = null;
    if (e.next == null)
    newTab[e.hash & (newCap - 1)] = e;
    else if (e instanceof TreeNode)
    ((TreeNode<K,V>)e).split(this, newTab, j, oldCap);
    else { // preserve order
    Node<K,V> loHead = null, loTail = null;
    Node<K,V> hiHead = null, hiTail = null;
    Node<K,V> next;
    do {
    next = e.next;
    if ((e.hash & oldCap) == 0) {
    if (loTail == null)
    loHead = e;
    else
    loTail.next = e;
    loTail = e;
    }
    else {
    if (hiTail == null)
    hiHead = e;
    else
    hiTail.next = e;
    hiTail = e;
    }
    } while ((e = next) != null);
    if (loTail != null) {
    loTail.next = null;
    newTab[j] = loHead;
    }
    if (hiTail != null) {
    hiTail.next = null;
    newTab[j + oldCap] = hiHead;
    }
    }
    }
    }
    }
    return newTab;
    }

    /**
    * Replaces all linked nodes in bin at index for given hash unless
    * table is too small, in which case resizes instead.
    */
    final void treeifyBin(Node<K,V>[] tab, int hash) {
    int n, index; Node<K,V> e;
    if (tab == null || (n = tab.length) < MIN_TREEIFY_CAPACITY)
    resize();
    else if ((e = tab[index = (n - 1) & hash]) != null) {
    TreeNode<K,V> hd = null, tl = null;
    do {
    TreeNode<K,V> p = replacementTreeNode(e, null);
    if (tl == null)
    hd = p;
    else {
    p.prev = tl;
    tl.next = p;
    }
    tl = p;
    } while ((e = e.next) != null);
    if ((tab[index] = hd) != null)
    hd.treeify(tab);
    }
    }

    /**
    * Copies all of the mappings from the specified map to this map.
    * These mappings will replace any mappings that this map had for
    * any of the keys currently in the specified map.
    *
    * @param m mappings to be stored in this map
    * @throws NullPointerException if the specified map is null
    */
    public void putAll(Map<? extends K, ? extends V> m) {
    putMapEntries(m, true);
    }

    /**
    * Removes the mapping for the specified key from this map if present.
    *
    * @param key key whose mapping is to be removed from the map
    * @return the previous value associated with {@code key}, or
    * {@code null} if there was no mapping for {@code key}.
    * (A {@code null} return can also indicate that the map
    * previously associated {@code null} with {@code key}.)
    */
    public V remove(Object key) {
    Node<K,V> e;
    return (e = removeNode(hash(key), key, null, false, true)) == null ?
    null : e.value;
    }

    /**
    * Implements Map.remove and related methods.
    *
    * @param hash hash for key
    * @param key the key
    * @param value the value to match if matchValue, else ignored
    * @param matchValue if true only remove if value is equal
    * @param movable if false do not move other nodes while removing
    * @return the node, or null if none
    */
    final Node<K,V> removeNode(int hash, Object key, Object value,
    boolean matchValue, boolean movable) {
    Node<K,V>[] tab; Node<K,V> p; int n, index;
    if ((tab = table) != null && (n = tab.length) > 0 &&
    (p = tab[index = (n - 1) & hash]) != null) {
    Node<K,V> node = null, e; K k; V v;
    if (p.hash == hash &&
    ((k = p.key) == key || (key != null && key.equals(k))))
    node = p;
    else if ((e = p.next) != null) {
    if (p instanceof TreeNode)
    node = ((TreeNode<K,V>)p).getTreeNode(hash, key);
    else {
    do {
    if (e.hash == hash &&
    ((k = e.key) == key ||
    (key != null && key.equals(k)))) {
    node = e;
    break;
    }
    p = e;
    } while ((e = e.next) != null);
    }
    }
    if (node != null && (!matchValue || (v = node.value) == value ||
    (value != null && value.equals(v)))) {
    if (node instanceof TreeNode)
    ((TreeNode<K,V>)node).removeTreeNode(this, tab, movable);
    else if (node == p)
    tab[index] = node.next;
    else
    p.next = node.next;
    ++modCount;
    --size;
    afterNodeRemoval(node);
    return node;
    }
    }
    return null;
    }

    /**
    * Removes all of the mappings from this map.
    * The map will be empty after this call returns.
    */
    public void clear() {
    Node<K,V>[] tab;
    modCount++;
    if ((tab = table) != null && size > 0) {
    size = 0;
    for (int i = 0; i < tab.length; ++i)
    tab[i] = null;
    }
    }

    /**
    * Returns {@code true} if this map maps one or more keys to the
    * specified value.
    *
    * @param value value whose presence in this map is to be tested
    * @return {@code true} if this map maps one or more keys to the
    * specified value
    */
    public boolean containsValue(Object value) {
    Node<K,V>[] tab; V v;
    if ((tab = table) != null && size > 0) {
    for (Node<K,V> e : tab) {
    for (; e != null; e = e.next) {
    if ((v = e.value) == value ||
    (value != null && value.equals(v)))
    return true;
    }
    }
    }
    return false;
    }

    /**
    * Returns a {@link Set} view of the keys contained in this map.
    * The set is backed by the map, so changes to the map are
    * reflected in the set, and vice-versa. If the map is modified
    * while an iteration over the set is in progress (except through
    * the iterator's own {@code remove} operation), the results of
    * the iteration are undefined. The set supports element removal,
    * which removes the corresponding mapping from the map, via the
    * {@code Iterator.remove}, {@code Set.remove},
    * {@code removeAll}, {@code retainAll}, and {@code clear}
    * operations. It does not support the {@code add} or {@code addAll}
    * operations.
    *
    * @return a set view of the keys contained in this map
    */
    public Set<K> keySet() {
    Set<K> ks = keySet;
    if (ks == null) {
    ks = new KeySet();
    keySet = ks;
    }
    return ks;
    }

    /**
    * Prepares the array for {@link Collection#toArray(Object[])} implementation.
    * If supplied array is smaller than this map size, a new array is allocated.
    * If supplied array is bigger than this map size, a null is written at size index.
    *
    * @param a an original array passed to {@code toArray()} method
    * @param <T> type of array elements
    * @return an array ready to be filled and returned from {@code toArray()} method.
    */
    @SuppressWarnings("unchecked")
    final <T> T[] prepareArray(T[] a) {
    int size = this.size;
    if (a.length < size) {
    return (T[]) java.lang.reflect.Array
    .newInstance(a.getClass().getComponentType(), size);
    }
    if (a.length > size) {
    a[size] = null;
    }
    return a;
    }

    /**
    * Fills an array with this map keys and returns it. This method assumes
    * that input array is big enough to fit all the keys. Use
    * {@link #prepareArray(Object[])} to ensure this.
    *
    * @param a an array to fill
    * @param <T> type of array elements
    * @return supplied array
    */
    <T> T[] keysToArray(T[] a) {
    Object[] r = a;
    Node<K,V>[] tab;
    int idx = 0;
    if (size > 0 && (tab = table) != null) {
    for (Node<K,V> e : tab) {
    for (; e != null; e = e.next) {
    r[idx++] = e.key;
    }
    }
    }
    return a;
    }

    /**
    * Fills an array with this map values and returns it. This method assumes
    * that input array is big enough to fit all the values. Use
    * {@link #prepareArray(Object[])} to ensure this.
    *
    * @param a an array to fill
    * @param <T> type of array elements
    * @return supplied array
    */
    <T> T[] valuesToArray(T[] a) {
    Object[] r = a;
    Node<K,V>[] tab;
    int idx = 0;
    if (size > 0 && (tab = table) != null) {
    for (Node<K,V> e : tab) {
    for (; e != null; e = e.next) {
    r[idx++] = e.value;
    }
    }
    }
    return a;
    }

    final class KeySet extends AbstractSet<K> {
    public final int size() { return size; }
    public final void clear() { HashMap.this.clear(); }
    public final Iterator<K> iterator() { return new KeyIterator(); }
    public final boolean contains(Object o) { return containsKey(o); }
    public final boolean remove(Object key) {
    return removeNode(hash(key), key, null, false, true) != null;
    }
    public final Spliterator<K> spliterator() {
    return new KeySpliterator<>(HashMap.this, 0, -1, 0, 0);
    }

    public Object[] toArray() {
    return keysToArray(new Object[size]);
    }

    public <T> T[] toArray(T[] a) {
    return keysToArray(prepareArray(a));
    }

    public final void forEach(Consumer<? super K> action) {
    Node<K,V>[] tab;
    if (action == null)
    throw new NullPointerException();
    if (size > 0 && (tab = table) != null) {
    int mc = modCount;
    for (Node<K,V> e : tab) {
    for (; e != null; e = e.next)
    action.accept(e.key);
    }
    if (modCount != mc)
    throw new ConcurrentModificationException();
    }
    }
    }

    /**
    * Returns a {@link Collection} view of the values contained in this map.
    * The collection is backed by the map, so changes to the map are
    * reflected in the collection, and vice-versa. If the map is
    * modified while an iteration over the collection is in progress
    * (except through the iterator's own {@code remove} operation),
    * the results of the iteration are undefined. The collection
    * supports element removal, which removes the corresponding
    * mapping from the map, via the {@code Iterator.remove},
    * {@code Collection.remove}, {@code removeAll},
    * {@code retainAll} and {@code clear} operations. It does not
    * support the {@code add} or {@code addAll} operations.
    *
    * @return a view of the values contained in this map
    */
    public Collection<V> values() {
    Collection<V> vs = values;
    if (vs == null) {
    vs = new Values();
    values = vs;
    }
    return vs;
    }

    final class Values extends AbstractCollection<V> {
    public final int size() { return size; }
    public final void clear() { HashMap.this.clear(); }
    public final Iterator<V> iterator() { return new ValueIterator(); }
    public final boolean contains(Object o) { return containsValue(o); }
    public final Spliterator<V> spliterator() {
    return new ValueSpliterator<>(HashMap.this, 0, -1, 0, 0);
    }

    public Object[] toArray() {
    return valuesToArray(new Object[size]);
    }

    public <T> T[] toArray(T[] a) {
    return valuesToArray(prepareArray(a));
    }

    public final void forEach(Consumer<? super V> action) {
    Node<K,V>[] tab;
    if (action == null)
    throw new NullPointerException();
    if (size > 0 && (tab = table) != null) {
    int mc = modCount;
    for (Node<K,V> e : tab) {
    for (; e != null; e = e.next)
    action.accept(e.value);
    }
    if (modCount != mc)
    throw new ConcurrentModificationException();
    }
    }
    }

    /**
    * Returns a {@link Set} view of the mappings contained in this map.
    * The set is backed by the map, so changes to the map are
    * reflected in the set, and vice-versa. If the map is modified
    * while an iteration over the set is in progress (except through
    * the iterator's own {@code remove} operation, or through the
    * {@code setValue} operation on a map entry returned by the
    * iterator) the results of the iteration are undefined. The set
    * supports element removal, which removes the corresponding
    * mapping from the map, via the {@code Iterator.remove},
    * {@code Set.remove}, {@code removeAll}, {@code retainAll} and
    * {@code clear} operations. It does not support the
    * {@code add} or {@code addAll} operations.
    *
    * @return a set view of the mappings contained in this map
    */
    public Set<Map.Entry<K,V>> entrySet() {
    Set<Map.Entry<K,V>> es;
    return (es = entrySet) == null ? (entrySet = new EntrySet()) : es;
    }

    final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
    public final int size() { return size; }
    public final void clear() { HashMap.this.clear(); }
    public final Iterator<Map.Entry<K,V>> iterator() {
    return new EntryIterator();
    }
    public final boolean contains(Object o) {
    if (!(o instanceof Map.Entry))
    return false;
    Map.Entry<?,?> e = (Map.Entry<?,?>) o;
    Object key = e.getKey();
    Node<K,V> candidate = getNode(key);
    return candidate != null && candidate.equals(e);
    }
    public final boolean remove(Object o) {
    if (o instanceof Map.Entry) {
    Map.Entry<?,?> e = (Map.Entry<?,?>) o;
    Object key = e.getKey();
    Object value = e.getValue();
    return removeNode(hash(key), key, value, true, true) != null;
    }
    return false;
    }
    public final Spliterator<Map.Entry<K,V>> spliterator() {
    return new EntrySpliterator<>(HashMap.this, 0, -1, 0, 0);
    }
    public final void forEach(Consumer<? super Map.Entry<K,V>> action) {
    Node<K,V>[] tab;
    if (action == null)
    throw new NullPointerException();
    if (size > 0 && (tab = table) != null) {
    int mc = modCount;
    for (Node<K,V> e : tab) {
    for (; e != null; e = e.next)
    action.accept(e);
    }
    if (modCount != mc)
    throw new ConcurrentModificationException();
    }
    }
    }

    // Overrides of JDK8 Map extension methods

    @Override
    public V getOrDefault(Object key, V defaultValue) {
    Node<K,V> e;
    return (e = getNode(key)) == null ? defaultValue : e.value;
    }

    @Override
    public V putIfAbsent(K key, V value) {
    return putVal(hash(key), key, value, true, true);
    }

    @Override
    public boolean remove(Object key, Object value) {
    return removeNode(hash(key), key, value, true, true) != null;
    }

    @Override
    public boolean replace(K key, V oldValue, V newValue) {
    Node<K,V> e; V v;
    if ((e = getNode(key)) != null &&
    ((v = e.value) == oldValue || (v != null && v.equals(oldValue)))) {
    e.value = newValue;
    afterNodeAccess(e);
    return true;
    }
    return false;
    }

    @Override
    public V replace(K key, V value) {
    Node<K,V> e;
    if ((e = getNode(key)) != null) {
    V oldValue = e.value;
    e.value = value;
    afterNodeAccess(e);
    return oldValue;
    }
    return null;
    }

    /**
    * {@inheritDoc}
    *
    * <p>This method will, on a best-effort basis, throw a
    * {@link ConcurrentModificationException} if it is detected that the
    * mapping function modifies this map during computation.
    *
    * @throws ConcurrentModificationException if it is detected that the
    * mapping function modified this map
    */
    @Override
    public V computeIfAbsent(K key,
    Function<? super K, ? extends V> mappingFunction) {
    if (mappingFunction == null)
    throw new NullPointerException();
    int hash = hash(key);
    Node<K,V>[] tab; Node<K,V> first; int n, i;
    int binCount = 0;
    TreeNode<K,V> t = null;
    Node<K,V> old = null;
    if (size > threshold || (tab = table) == null ||
    (n = tab.length) == 0)
    n = (tab = resize()).length;
    if ((first = tab[i = (n - 1) & hash]) != null) {
    if (first instanceof TreeNode)
    old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key);
    else {
    Node<K,V> e = first; K k;
    do {
    if (e.hash == hash &&
    ((k = e.key) == key || (key != null && key.equals(k)))) {
    old = e;
    break;
    }
    ++binCount;
    } while ((e = e.next) != null);
    }
    V oldValue;
    if (old != null && (oldValue = old.value) != null) {
    afterNodeAccess(old);
    return oldValue;
    }
    }
    int mc = modCount;
    V v = mappingFunction.apply(key);
    if (mc != modCount) { throw new ConcurrentModificationException(); }
    if (v == null) {
    return null;
    } else if (old != null) {
    old.value = v;
    afterNodeAccess(old);
    return v;
    }
    else if (t != null)
    t.putTreeVal(this, tab, hash, key, v);
    else {
    tab[i] = newNode(hash, key, v, first);
    if (binCount >= TREEIFY_THRESHOLD - 1)
    treeifyBin(tab, hash);
    }
    modCount = mc + 1;
    ++size;
    afterNodeInsertion(true);
    return v;
    }

    /**
    * {@inheritDoc}
    *
    * <p>This method will, on a best-effort basis, throw a
    * {@link ConcurrentModificationException} if it is detected that the
    * remapping function modifies this map during computation.
    *
    * @throws ConcurrentModificationException if it is detected that the
    * remapping function modified this map
    */
    @Override
    public V computeIfPresent(K key,
    BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
    if (remappingFunction == null)
    throw new NullPointerException();
    Node<K,V> e; V oldValue;
    if ((e = getNode(key)) != null &&
    (oldValue = e.value) != null) {
    int mc = modCount;
    V v = remappingFunction.apply(key, oldValue);
    if (mc != modCount) { throw new ConcurrentModificationException(); }
    if (v != null) {
    e.value = v;
    afterNodeAccess(e);
    return v;
    }
    else {
    int hash = hash(key);
    removeNode(hash, key, null, false, true);
    }
    }
    return null;
    }

    /**
    * {@inheritDoc}
    *
    * <p>This method will, on a best-effort basis, throw a
    * {@link ConcurrentModificationException} if it is detected that the
    * remapping function modifies this map during computation.
    *
    * @throws ConcurrentModificationException if it is detected that the
    * remapping function modified this map
    */
    @Override
    public V compute(K key,
    BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
    if (remappingFunction == null)
    throw new NullPointerException();
    int hash = hash(key);
    Node<K,V>[] tab; Node<K,V> first; int n, i;
    int binCount = 0;
    TreeNode<K,V> t = null;
    Node<K,V> old = null;
    if (size > threshold || (tab = table) == null ||
    (n = tab.length) == 0)
    n = (tab = resize()).length;
    if ((first = tab[i = (n - 1) & hash]) != null) {
    if (first instanceof TreeNode)
    old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key);
    else {
    Node<K,V> e = first; K k;
    do {
    if (e.hash == hash &&
    ((k = e.key) == key || (key != null && key.equals(k)))) {
    old = e;
    break;
    }
    ++binCount;
    } while ((e = e.next) != null);
    }
    }
    V oldValue = (old == null) ? null : old.value;
    int mc = modCount;
    V v = remappingFunction.apply(key, oldValue);
    if (mc != modCount) { throw new ConcurrentModificationException(); }
    if (old != null) {
    if (v != null) {
    old.value = v;
    afterNodeAccess(old);
    }
    else
    removeNode(hash, key, null, false, true);
    }
    else if (v != null) {
    if (t != null)
    t.putTreeVal(this, tab, hash, key, v);
    else {
    tab[i] = newNode(hash, key, v, first);
    if (binCount >= TREEIFY_THRESHOLD - 1)
    treeifyBin(tab, hash);
    }
    modCount = mc + 1;
    ++size;
    afterNodeInsertion(true);
    }
    return v;
    }

    /**
    * {@inheritDoc}
    *
    * <p>This method will, on a best-effort basis, throw a
    * {@link ConcurrentModificationException} if it is detected that the
    * remapping function modifies this map during computation.
    *
    * @throws ConcurrentModificationException if it is detected that the
    * remapping function modified this map
    */
    @Override
    public V merge(K key, V value,
    BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
    if (value == null || remappingFunction == null)
    throw new NullPointerException();
    int hash = hash(key);
    Node<K,V>[] tab; Node<K,V> first; int n, i;
    int binCount = 0;
    TreeNode<K,V> t = null;
    Node<K,V> old = null;
    if (size > threshold || (tab = table) == null ||
    (n = tab.length) == 0)
    n = (tab = resize()).length;
    if ((first = tab[i = (n - 1) & hash]) != null) {
    if (first instanceof TreeNode)
    old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key);
    else {
    Node<K,V> e = first; K k;
    do {
    if (e.hash == hash &&
    ((k = e.key) == key || (key != null && key.equals(k)))) {
    old = e;
    break;
    }
    ++binCount;
    } while ((e = e.next) != null);
    }
    }
    if (old != null) {
    V v;
    if (old.value != null) {
    int mc = modCount;
    v = remappingFunction.apply(old.value, value);
    if (mc != modCount) {
    throw new ConcurrentModificationException();
    }
    } else {
    v = value;
    }
    if (v != null) {
    old.value = v;
    afterNodeAccess(old);
    }
    else
    removeNode(hash, key, null, false, true);
    return v;
    } else {
    if (t != null)
    t.putTreeVal(this, tab, hash, key, value);
    else {
    tab[i] = newNode(hash, key, value, first);
    if (binCount >= TREEIFY_THRESHOLD - 1)
    treeifyBin(tab, hash);
    }
    ++modCount;
    ++size;
    afterNodeInsertion(true);
    return value;
    }
    }

    @Override
    public void forEach(BiConsumer<? super K, ? super V> action) {
    Node<K,V>[] tab;
    if (action == null)
    throw new NullPointerException();
    if (size > 0 && (tab = table) != null) {
    int mc = modCount;
    for (Node<K,V> e : tab) {
    for (; e != null; e = e.next)
    action.accept(e.key, e.value);
    }
    if (modCount != mc)
    throw new ConcurrentModificationException();
    }
    }

    @Override
    public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
    Node<K,V>[] tab;
    if (function == null)
    throw new NullPointerException();
    if (size > 0 && (tab = table) != null) {
    int mc = modCount;
    for (Node<K,V> e : tab) {
    for (; e != null; e = e.next) {
    e.value = function.apply(e.key, e.value);
    }
    }
    if (modCount != mc)
    throw new ConcurrentModificationException();
    }
    }

    /* ------------------------------------------------------------ */
    // Cloning and serialization

    /**
    * Returns a shallow copy of this {@code HashMap} instance: the keys and
    * values themselves are not cloned.
    *
    * @return a shallow copy of this map
    */
    @SuppressWarnings("unchecked")
    @Override
    public Object clone() {
    HashMap<K,V> result;
    try {
    result = (HashMap<K,V>)super.clone();
    } catch (CloneNotSupportedException e) {
    // this shouldn't happen, since we are Cloneable
    throw new InternalError(e);
    }
    result.reinitialize();
    result.putMapEntries(this, false);
    return result;
    }

    // These methods are also used when serializing HashSets
    final float loadFactor() { return loadFactor; }
    final int capacity() {
    return (table != null) ? table.length :
    (threshold > 0) ? threshold :
    DEFAULT_INITIAL_CAPACITY;
    }

    /**
    * Saves this map to a stream (that is, serializes it).
    *
    * @param s the stream
    * @throws IOException if an I/O error occurs
    * @serialData The <i>capacity</i> of the HashMap (the length of the
    * bucket array) is emitted (int), followed by the
    * <i>size</i> (an int, the number of key-value
    * mappings), followed by the key (Object) and value (Object)
    * for each key-value mapping. The key-value mappings are
    * emitted in no particular order.
    */
    @java.io.Serial
    private void writeObject(java.io.ObjectOutputStream s)
    throws IOException {
    int buckets = capacity();
    // Write out the threshold, loadfactor, and any hidden stuff
    s.defaultWriteObject();
    s.writeInt(buckets);
    s.writeInt(size);
    internalWriteEntries(s);
    }

    /**
    * Reconstitutes this map from a stream (that is, deserializes it).
    * @param s the stream
    * @throws ClassNotFoundException if the class of a serialized object
    * could not be found
    * @throws IOException if an I/O error occurs
    */
    @java.io.Serial
    private void readObject(java.io.ObjectInputStream s)
    throws IOException, ClassNotFoundException {
    // Read in the threshold (ignored), loadfactor, and any hidden stuff
    s.defaultReadObject();
    reinitialize();
    if (loadFactor <= 0 || Float.isNaN(loadFactor))
    throw new InvalidObjectException("Illegal load factor: " +
    loadFactor);
    s.readInt(); // Read and ignore number of buckets
    int mappings = s.readInt(); // Read number of mappings (size)
    if (mappings < 0)
    throw new InvalidObjectException("Illegal mappings count: " +
    mappings);
    else if (mappings > 0) { // (if zero, use defaults)
    // Size the table using given load factor only if within
    // range of 0.25...4.0
    float lf = Math.min(Math.max(0.25f, loadFactor), 4.0f);
    float fc = (float)mappings / lf + 1.0f;
    int cap = ((fc < DEFAULT_INITIAL_CAPACITY) ?
    DEFAULT_INITIAL_CAPACITY :
    (fc >= MAXIMUM_CAPACITY) ?
    MAXIMUM_CAPACITY :
    tableSizeFor((int)fc));
    float ft = (float)cap * lf;
    threshold = ((cap < MAXIMUM_CAPACITY && ft < MAXIMUM_CAPACITY) ?
    (int)ft : Integer.MAX_VALUE);

    // Check Map.Entry[].class since it's the nearest public type to
    // what we're actually creating.
    SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Map.Entry[].class, cap);
    @SuppressWarnings({"rawtypes","unchecked"})
    Node<K,V>[] tab = (Node<K,V>[])new Node[cap];
    table = tab;

    // Read the keys and values, and put the mappings in the HashMap
    for (int i = 0; i < mappings; i++) {
    @SuppressWarnings("unchecked")
    K key = (K) s.readObject();
    @SuppressWarnings("unchecked")
    V value = (V) s.readObject();
    putVal(hash(key), key, value, false, false);
    }
    }
    }

    /* ------------------------------------------------------------ */
    // iterators

    abstract class HashIterator {
    Node<K,V> next; // next entry to return
    Node<K,V> current; // current entry
    int expectedModCount; // for fast-fail
    int index; // current slot

    HashIterator() {
    expectedModCount = modCount;
    Node<K,V>[] t = table;
    current = next = null;
    index = 0;
    if (t != null && size > 0) { // advance to first entry
    do {} while (index < t.length && (next = t[index++]) == null);
    }
    }

    public final boolean hasNext() {
    return next != null;
    }

    final Node<K,V> nextNode() {
    Node<K,V>[] t;
    Node<K,V> e = next;
    if (modCount != expectedModCount)
    throw new ConcurrentModificationException();
    if (e == null)
    throw new NoSuchElementException();
    if ((next = (current = e).next) == null && (t = table) != null) {
    do {} while (index < t.length && (next = t[index++]) == null);
    }
    return e;
    }

    public final void remove() {
    Node<K,V> p = current;
    if (p == null)
    throw new IllegalStateException();
    if (modCount != expectedModCount)
    throw new ConcurrentModificationException();
    current = null;
    removeNode(p.hash, p.key, null, false, false);
    expectedModCount = modCount;
    }
    }

    final class KeyIterator extends HashIterator
    implements Iterator<K> {
    public final K next() { return nextNode().key; }
    }

    final class ValueIterator extends HashIterator
    implements Iterator<V> {
    public final V next() { return nextNode().value; }
    }

    final class EntryIterator extends HashIterator
    implements Iterator<Map.Entry<K,V>> {
    public final Map.Entry<K,V> next() { return nextNode(); }
    }

    /* ------------------------------------------------------------ */
    // spliterators

    static class HashMapSpliterator<K,V> {
    final HashMap<K,V> map;
    Node<K,V> current; // current node
    int index; // current index, modified on advance/split
    int fence; // one past last index
    int est; // size estimate
    int expectedModCount; // for comodification checks

    HashMapSpliterator(HashMap<K,V> m, int origin,
    int fence, int est,
    int expectedModCount) {
    this.map = m;
    this.index = origin;
    this.fence = fence;
    this.est = est;
    this.expectedModCount = expectedModCount;
    }

    final int getFence() { // initialize fence and size on first use
    int hi;
    if ((hi = fence) < 0) {
    HashMap<K,V> m = map;
    est = m.size;
    expectedModCount = m.modCount;
    Node<K,V>[] tab = m.table;
    hi = fence = (tab == null) ? 0 : tab.length;
    }
    return hi;
    }

    public final long estimateSize() {
    getFence(); // force init
    return (long) est;
    }
    }

    static final class KeySpliterator<K,V>
    extends HashMapSpliterator<K,V>
    implements Spliterator<K> {
    KeySpliterator(HashMap<K,V> m, int origin, int fence, int est,
    int expectedModCount) {
    super(m, origin, fence, est, expectedModCount);
    }

    public KeySpliterator<K,V> trySplit() {
    int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
    return (lo >= mid || current != null) ? null :
    new KeySpliterator<>(map, lo, index = mid, est >>>= 1,
    expectedModCount);
    }

    public void forEachRemaining(Consumer<? super K> action) {
    int i, hi, mc;
    if (action == null)
    throw new NullPointerException();
    HashMap<K,V> m = map;
    Node<K,V>[] tab = m.table;
    if ((hi = fence) < 0) {
    mc = expectedModCount = m.modCount;
    hi = fence = (tab == null) ? 0 : tab.length;
    }
    else
    mc = expectedModCount;
    if (tab != null && tab.length >= hi &&
    (i = index) >= 0 && (i < (index = hi) || current != null)) {
    Node<K,V> p = current;
    current = null;
    do {
    if (p == null)
    p = tab[i++];
    else {
    action.accept(p.key);
    p = p.next;
    }
    } while (p != null || i < hi);
    if (m.modCount != mc)
    throw new ConcurrentModificationException();
    }
    }

    public boolean tryAdvance(Consumer<? super K> action) {
    int hi;
    if (action == null)
    throw new NullPointerException();
    Node<K,V>[] tab = map.table;
    if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
    while (current != null || index < hi) {
    if (current == null)
    current = tab[index++];
    else {
    K k = current.key;
    current = current.next;
    action.accept(k);
    if (map.modCount != expectedModCount)
    throw new ConcurrentModificationException();
    return true;
    }
    }
    }
    return false;
    }

    public int characteristics() {
    return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) |
    Spliterator.DISTINCT;
    }
    }

    static final class ValueSpliterator<K,V>
    extends HashMapSpliterator<K,V>
    implements Spliterator<V> {
    ValueSpliterator(HashMap<K,V> m, int origin, int fence, int est,
    int expectedModCount) {
    super(m, origin, fence, est, expectedModCount);
    }

    public ValueSpliterator<K,V> trySplit() {
    int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
    return (lo >= mid || current != null) ? null :
    new ValueSpliterator<>(map, lo, index = mid, est >>>= 1,
    expectedModCount);
    }

    public void forEachRemaining(Consumer<? super V> action) {
    int i, hi, mc;
    if (action == null)
    throw new NullPointerException();
    HashMap<K,V> m = map;
    Node<K,V>[] tab = m.table;
    if ((hi = fence) < 0) {
    mc = expectedModCount = m.modCount;
    hi = fence = (tab == null) ? 0 : tab.length;
    }
    else
    mc = expectedModCount;
    if (tab != null && tab.length >= hi &&
    (i = index) >= 0 && (i < (index = hi) || current != null)) {
    Node<K,V> p = current;
    current = null;
    do {
    if (p == null)
    p = tab[i++];
    else {
    action.accept(p.value);
    p = p.next;
    }
    } while (p != null || i < hi);
    if (m.modCount != mc)
    throw new ConcurrentModificationException();
    }
    }

    public boolean tryAdvance(Consumer<? super V> action) {
    int hi;
    if (action == null)
    throw new NullPointerException();
    Node<K,V>[] tab = map.table;
    if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
    while (current != null || index < hi) {
    if (current == null)
    current = tab[index++];
    else {
    V v = current.value;
    current = current.next;
    action.accept(v);
    if (map.modCount != expectedModCount)
    throw new ConcurrentModificationException();
    return true;
    }
    }
    }
    return false;
    }

    public int characteristics() {
    return (fence < 0 || est == map.size ? Spliterator.SIZED : 0);
    }
    }

    static final class EntrySpliterator<K,V>
    extends HashMapSpliterator<K,V>
    implements Spliterator<Map.Entry<K,V>> {
    EntrySpliterator(HashMap<K,V> m, int origin, int fence, int est,
    int expectedModCount) {
    super(m, origin, fence, est, expectedModCount);
    }

    public EntrySpliterator<K,V> trySplit() {
    int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
    return (lo >= mid || current != null) ? null :
    new EntrySpliterator<>(map, lo, index = mid, est >>>= 1,
    expectedModCount);
    }

    public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
    int i, hi, mc;
    if (action == null)
    throw new NullPointerException();
    HashMap<K,V> m = map;
    Node<K,V>[] tab = m.table;
    if ((hi = fence) < 0) {
    mc = expectedModCount = m.modCount;
    hi = fence = (tab == null) ? 0 : tab.length;
    }
    else
    mc = expectedModCount;
    if (tab != null && tab.length >= hi &&
    (i = index) >= 0 && (i < (index = hi) || current != null)) {
    Node<K,V> p = current;
    current = null;
    do {
    if (p == null)
    p = tab[i++];
    else {
    action.accept(p);
    p = p.next;
    }
    } while (p != null || i < hi);
    if (m.modCount != mc)
    throw new ConcurrentModificationException();
    }
    }

    public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
    int hi;
    if (action == null)
    throw new NullPointerException();
    Node<K,V>[] tab = map.table;
    if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
    while (current != null || index < hi) {
    if (current == null)
    current = tab[index++];
    else {
    Node<K,V> e = current;
    current = current.next;
    action.accept(e);
    if (map.modCount != expectedModCount)
    throw new ConcurrentModificationException();
    return true;
    }
    }
    }
    return false;
    }

    public int characteristics() {
    return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) |
    Spliterator.DISTINCT;
    }
    }

    /* ------------------------------------------------------------ */
    // LinkedHashMap support


    /*
    * The following package-protected methods are designed to be
    * overridden by LinkedHashMap, but not by any other subclass.
    * Nearly all other internal methods are also package-protected
    * but are declared final, so can be used by LinkedHashMap, view
    * classes, and HashSet.
    */

    // Create a regular (non-tree) node
    Node<K,V> newNode(int hash, K key, V value, Node<K,V> next) {
    return new Node<>(hash, key, value, next);
    }

    // For conversion from TreeNodes to plain nodes
    Node<K,V> replacementNode(Node<K,V> p, Node<K,V> next) {
    return new Node<>(p.hash, p.key, p.value, next);
    }

    // Create a tree bin node
    TreeNode<K,V> newTreeNode(int hash, K key, V value, Node<K,V> next) {
    return new TreeNode<>(hash, key, value, next);
    }

    // For treeifyBin
    TreeNode<K,V> replacementTreeNode(Node<K,V> p, Node<K,V> next) {
    return new TreeNode<>(p.hash, p.key, p.value, next);
    }

    /**
    * Reset to initial default state. Called by clone and readObject.
    */
    void reinitialize() {
    table = null;
    entrySet = null;
    keySet = null;
    values = null;
    modCount = 0;
    threshold = 0;
    size = 0;
    }

    // Callbacks to allow LinkedHashMap post-actions
    void afterNodeAccess(Node<K,V> p) { }
    void afterNodeInsertion(boolean evict) { }
    void afterNodeRemoval(Node<K,V> p) { }

    // Called only from writeObject, to ensure compatible ordering.
    void internalWriteEntries(java.io.ObjectOutputStream s) throws IOException {
    Node<K,V>[] tab;
    if (size > 0 && (tab = table) != null) {
    for (Node<K,V> e : tab) {
    for (; e != null; e = e.next) {
    s.writeObject(e.key);
    s.writeObject(e.value);
    }
    }
    }
    }

    /* ------------------------------------------------------------ */
    // Tree bins

    /**
    * Entry for Tree bins. Extends LinkedHashMap.Entry (which in turn
    * extends Node) so can be used as extension of either regular or
    * linked node.
    */
    static final class TreeNode<K,V> extends LinkedHashMap.Entry<K,V> {
    TreeNode<K,V> parent; // red-black tree links
    TreeNode<K,V> left;
    TreeNode<K,V> right;
    TreeNode<K,V> prev; // needed to unlink next upon deletion
    boolean red;
    TreeNode(int hash, K key, V val, Node<K,V> next) {
    super(hash, key, val, next);
    }

    /**
    * Returns root of tree containing this node.
    */
    final TreeNode<K,V> root() {
    for (TreeNode<K,V> r = this, p;;) {
    if ((p = r.parent) == null)
    return r;
    r = p;
    }
    }

    /**
    * Ensures that the given root is the first node of its bin.
    */
    static <K,V> void moveRootToFront(Node<K,V>[] tab, TreeNode<K,V> root) {
    int n;
    if (root != null && tab != null && (n = tab.length) > 0) {
    int index = (n - 1) & root.hash;
    TreeNode<K,V> first = (TreeNode<K,V>)tab[index];
    if (root != first) {
    Node<K,V> rn;
    tab[index] = root;
    TreeNode<K,V> rp = root.prev;
    if ((rn = root.next) != null)
    ((TreeNode<K,V>)rn).prev = rp;
    if (rp != null)
    rp.next = rn;
    if (first != null)
    first.prev = root;
    root.next = first;
    root.prev = null;
    }
    assert checkInvariants(root);
    }
    }

    /**
    * Finds the node starting at root p with the given hash and key.
    * The kc argument caches comparableClassFor(key) upon first use
    * comparing keys.
    */
    final TreeNode<K,V> find(int h, Object k, Class<?> kc) {
    TreeNode<K,V> p = this;
    do {
    int ph, dir; K pk;
    TreeNode<K,V> pl = p.left, pr = p.right, q;
    if ((ph = p.hash) > h)
    p = pl;
    else if (ph < h)
    p = pr;
    else if ((pk = p.key) == k || (k != null && k.equals(pk)))
    return p;
    else if (pl == null)
    p = pr;
    else if (pr == null)
    p = pl;
    else if ((kc != null ||
    (kc = comparableClassFor(k)) != null) &&
    (dir = compareComparables(kc, k, pk)) != 0)
    p = (dir < 0) ? pl : pr;
    else if ((q = pr.find(h, k, kc)) != null)
    return q;
    else
    p = pl;
    } while (p != null);
    return null;
    }

    /**
    * Calls find for root node.
    */
    final TreeNode<K,V> getTreeNode(int h, Object k) {
    return ((parent != null) ? root() : this).find(h, k, null);
    }

    /**
    * Tie-breaking utility for ordering insertions when equal
    * hashCodes and non-comparable. We don't require a total
    * order, just a consistent insertion rule to maintain
    * equivalence across rebalancings. Tie-breaking further than
    * necessary simplifies testing a bit.
    */
    static int tieBreakOrder(Object a, Object b) {
    int d;
    if (a == null || b == null ||
    (d = a.getClass().getName().
    compareTo(b.getClass().getName())) == 0)
    d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
    -1 : 1);
    return d;
    }

    /**
    * Forms tree of the nodes linked from this node.
    */
    final void treeify(Node<K,V>[] tab) {
    TreeNode<K,V> root = null;
    for (TreeNode<K,V> x = this, next; x != null; x = next) {
    next = (TreeNode<K,V>)x.next;
    x.left = x.right = null;
    if (root == null) {
    x.parent = null;
    x.red = false;
    root = x;
    }
    else {
    K k = x.key;
    int h = x.hash;
    Class<?> kc = null;
    for (TreeNode<K,V> p = root;;) {
    int dir, ph;
    K pk = p.key;
    if ((ph = p.hash) > h)
    dir = -1;
    else if (ph < h)
    dir = 1;
    else if ((kc == null &&
    (kc = comparableClassFor(k)) == null) ||
    (dir = compareComparables(kc, k, pk)) == 0)
    dir = tieBreakOrder(k, pk);

    TreeNode<K,V> xp = p;
    if ((p = (dir <= 0) ? p.left : p.right) == null) {
    x.parent = xp;
    if (dir <= 0)
    xp.left = x;
    else
    xp.right = x;
    root = balanceInsertion(root, x);
    break;
    }
    }
    }
    }
    moveRootToFront(tab, root);
    }

    /**
    * Returns a list of non-TreeNodes replacing those linked from
    * this node.
    */
    final Node<K,V> untreeify(HashMap<K,V> map) {
    Node<K,V> hd = null, tl = null;
    for (Node<K,V> q = this; q != null; q = q.next) {
    Node<K,V> p = map.replacementNode(q, null);
    if (tl == null)
    hd = p;
    else
    tl.next = p;
    tl = p;
    }
    return hd;
    }

    /**
    * Tree version of putVal.
    */
    final TreeNode<K,V> putTreeVal(HashMap<K,V> map, Node<K,V>[] tab,
    int h, K k, V v) {
    Class<?> kc = null;
    boolean searched = false;
    TreeNode<K,V> root = (parent != null) ? root() : this;
    for (TreeNode<K,V> p = root;;) {
    int dir, ph; K pk;
    if ((ph = p.hash) > h)
    dir = -1;
    else if (ph < h)
    dir = 1;
    else if ((pk = p.key) == k || (k != null && k.equals(pk)))
    return p;
    else if ((kc == null &&
    (kc = comparableClassFor(k)) == null) ||
    (dir = compareComparables(kc, k, pk)) == 0) {
    if (!searched) {
    TreeNode<K,V> q, ch;
    searched = true;
    if (((ch = p.left) != null &&
    (q = ch.find(h, k, kc)) != null) ||
    ((ch = p.right) != null &&
    (q = ch.find(h, k, kc)) != null))
    return q;
    }
    dir = tieBreakOrder(k, pk);
    }

    TreeNode<K,V> xp = p;
    if ((p = (dir <= 0) ? p.left : p.right) == null) {
    Node<K,V> xpn = xp.next;
    TreeNode<K,V> x = map.newTreeNode(h, k, v, xpn);
    if (dir <= 0)
    xp.left = x;
    else
    xp.right = x;
    xp.next = x;
    x.parent = x.prev = xp;
    if (xpn != null)
    ((TreeNode<K,V>)xpn).prev = x;
    moveRootToFront(tab, balanceInsertion(root, x));
    return null;
    }
    }
    }

    /**
    * Removes the given node, that must be present before this call.
    * This is messier than typical red-black deletion code because we
    * cannot swap the contents of an interior node with a leaf
    * successor that is pinned by "next" pointers that are accessible
    * independently during traversal. So instead we swap the tree
    * linkages. If the current tree appears to have too few nodes,
    * the bin is converted back to a plain bin. (The test triggers
    * somewhere between 2 and 6 nodes, depending on tree structure).
    */
    final void removeTreeNode(HashMap<K,V> map, Node<K,V>[] tab,
    boolean movable) {
    int n;
    if (tab == null || (n = tab.length) == 0)
    return;
    int index = (n - 1) & hash;
    TreeNode<K,V> first = (TreeNode<K,V>)tab[index], root = first, rl;
    TreeNode<K,V> succ = (TreeNode<K,V>)next, pred = prev;
    if (pred == null)
    tab[index] = first = succ;
    else
    pred.next = succ;
    if (succ != null)
    succ.prev = pred;
    if (first == null)
    return;
    if (root.parent != null)
    root = root.root();
    if (root == null
    || (movable
    && (root.right == null
    || (rl = root.left) == null
    || rl.left == null))) {
    tab[index] = first.untreeify(map); // too small
    return;
    }
    TreeNode<K,V> p = this, pl = left, pr = right, replacement;
    if (pl != null && pr != null) {
    TreeNode<K,V> s = pr, sl;
    while ((sl = s.left) != null) // find successor
    s = sl;
    boolean c = s.red; s.red = p.red; p.red = c; // swap colors
    TreeNode<K,V> sr = s.right;
    TreeNode<K,V> pp = p.parent;
    if (s == pr) { // p was s's direct parent
    p.parent = s;
    s.right = p;
    }
    else {
    TreeNode<K,V> sp = s.parent;
    if ((p.parent = sp) != null) {
    if (s == sp.left)
    sp.left = p;
    else
    sp.right = p;
    }
    if ((s.right = pr) != null)
    pr.parent = s;
    }
    p.left = null;
    if ((p.right = sr) != null)
    sr.parent = p;
    if ((s.left = pl) != null)
    pl.parent = s;
    if ((s.parent = pp) == null)
    root = s;
    else if (p == pp.left)
    pp.left = s;
    else
    pp.right = s;
    if (sr != null)
    replacement = sr;
    else
    replacement = p;
    }
    else if (pl != null)
    replacement = pl;
    else if (pr != null)
    replacement = pr;
    else
    replacement = p;
    if (replacement != p) {
    TreeNode<K,V> pp = replacement.parent = p.parent;
    if (pp == null)
    (root = replacement).red = false;
    else if (p == pp.left)
    pp.left = replacement;
    else
    pp.right = replacement;
    p.left = p.right = p.parent = null;
    }

    TreeNode<K,V> r = p.red ? root : balanceDeletion(root, replacement);

    if (replacement == p) { // detach
    TreeNode<K,V> pp = p.parent;
    p.parent = null;
    if (pp != null) {
    if (p == pp.left)
    pp.left = null;
    else if (p == pp.right)
    pp.right = null;
    }
    }
    if (movable)
    moveRootToFront(tab, r);
    }

    /**
    * Splits nodes in a tree bin into lower and upper tree bins,
    * or untreeifies if now too small. Called only from resize;
    * see above discussion about split bits and indices.
    *
    * @param map the map
    * @param tab the table for recording bin heads
    * @param index the index of the table being split
    * @param bit the bit of hash to split on
    */
    final void split(HashMap<K,V> map, Node<K,V>[] tab, int index, int bit) {
    TreeNode<K,V> b = this;
    // Relink into lo and hi lists, preserving order
    TreeNode<K,V> loHead = null, loTail = null;
    TreeNode<K,V> hiHead = null, hiTail = null;
    int lc = 0, hc = 0;
    for (TreeNode<K,V> e = b, next; e != null; e = next) {
    next = (TreeNode<K,V>)e.next;
    e.next = null;
    if ((e.hash & bit) == 0) {
    if ((e.prev = loTail) == null)
    loHead = e;
    else
    loTail.next = e;
    loTail = e;
    ++lc;
    }
    else {
    if ((e.prev = hiTail) == null)
    hiHead = e;
    else
    hiTail.next = e;
    hiTail = e;
    ++hc;
    }
    }

    if (loHead != null) {
    if (lc <= UNTREEIFY_THRESHOLD)
    tab[index] = loHead.untreeify(map);
    else {
    tab[index] = loHead;
    if (hiHead != null) // (else is already treeified)
    loHead.treeify(tab);
    }
    }
    if (hiHead != null) {
    if (hc <= UNTREEIFY_THRESHOLD)
    tab[index + bit] = hiHead.untreeify(map);
    else {
    tab[index + bit] = hiHead;
    if (loHead != null)
    hiHead.treeify(tab);
    }
    }
    }

    /* ------------------------------------------------------------ */
    // Red-black tree methods, all adapted from CLR

    static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
    TreeNode<K,V> p) {
    TreeNode<K,V> r, pp, rl;
    if (p != null && (r = p.right) != null) {
    if ((rl = p.right = r.left) != null)
    rl.parent = p;
    if ((pp = r.parent = p.parent) == null)
    (root = r).red = false;
    else if (pp.left == p)
    pp.left = r;
    else
    pp.right = r;
    r.left = p;
    p.parent = r;
    }
    return root;
    }

    static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
    TreeNode<K,V> p) {
    TreeNode<K,V> l, pp, lr;
    if (p != null && (l = p.left) != null) {
    if ((lr = p.left = l.right) != null)
    lr.parent = p;
    if ((pp = l.parent = p.parent) == null)
    (root = l).red = false;
    else if (pp.right == p)
    pp.right = l;
    else
    pp.left = l;
    l.right = p;
    p.parent = l;
    }
    return root;
    }

    static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
    TreeNode<K,V> x) {
    x.red = true;
    for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
    if ((xp = x.parent) == null) {
    x.red = false;
    return x;
    }
    else if (!xp.red || (xpp = xp.parent) == null)
    return root;
    if (xp == (xppl = xpp.left)) {
    if ((xppr = xpp.right) != null && xppr.red) {
    xppr.red = false;
    xp.red = false;
    xpp.red = true;
    x = xpp;
    }
    else {
    if (x == xp.right) {
    root = rotateLeft(root, x = xp);
    xpp = (xp = x.parent) == null ? null : xp.parent;
    }
    if (xp != null) {
    xp.red = false;
    if (xpp != null) {
    xpp.red = true;
    root = rotateRight(root, xpp);
    }
    }
    }
    }
    else {
    if (xppl != null && xppl.red) {
    xppl.red = false;
    xp.red = false;
    xpp.red = true;
    x = xpp;
    }
    else {
    if (x == xp.left) {
    root = rotateRight(root, x = xp);
    xpp = (xp = x.parent) == null ? null : xp.parent;
    }
    if (xp != null) {
    xp.red = false;
    if (xpp != null) {
    xpp.red = true;
    root = rotateLeft(root, xpp);
    }
    }
    }
    }
    }
    }

    static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
    TreeNode<K,V> x) {
    for (TreeNode<K,V> xp, xpl, xpr;;) {
    if (x == null || x == root)
    return root;
    else if ((xp = x.parent) == null) {
    x.red = false;
    return x;
    }
    else if (x.red) {
    x.red = false;
    return root;
    }
    else if ((xpl = xp.left) == x) {
    if ((xpr = xp.right) != null && xpr.red) {
    xpr.red = false;
    xp.red = true;
    root = rotateLeft(root, xp);
    xpr = (xp = x.parent) == null ? null : xp.right;
    }
    if (xpr == null)
    x = xp;
    else {
    TreeNode<K,V> sl = xpr.left, sr = xpr.right;
    if ((sr == null || !sr.red) &&
    (sl == null || !sl.red)) {
    xpr.red = true;
    x = xp;
    }
    else {
    if (sr == null || !sr.red) {
    if (sl != null)
    sl.red = false;
    xpr.red = true;
    root = rotateRight(root, xpr);
    xpr = (xp = x.parent) == null ?
    null : xp.right;
    }
    if (xpr != null) {
    xpr.red = (xp == null) ? false : xp.red;
    if ((sr = xpr.right) != null)
    sr.red = false;
    }
    if (xp != null) {
    xp.red = false;
    root = rotateLeft(root, xp);
    }
    x = root;
    }
    }
    }
    else { // symmetric
    if (xpl != null && xpl.red) {
    xpl.red = false;
    xp.red = true;
    root = rotateRight(root, xp);
    xpl = (xp = x.parent) == null ? null : xp.left;
    }
    if (xpl == null)
    x = xp;
    else {
    TreeNode<K,V> sl = xpl.left, sr = xpl.right;
    if ((sl == null || !sl.red) &&
    (sr == null || !sr.red)) {
    xpl.red = true;
    x = xp;
    }
    else {
    if (sl == null || !sl.red) {
    if (sr != null)
    sr.red = false;
    xpl.red = true;
    root = rotateLeft(root, xpl);
    xpl = (xp = x.parent) == null ?
    null : xp.left;
    }
    if (xpl != null) {
    xpl.red = (xp == null) ? false : xp.red;
    if ((sl = xpl.left) != null)
    sl.red = false;
    }
    if (xp != null) {
    xp.red = false;
    root = rotateRight(root, xp);
    }
    x = root;
    }
    }
    }
    }
    }

    /**
    * Recursive invariant check
    */
    static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
    TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
    tb = t.prev, tn = (TreeNode<K,V>)t.next;
    if (tb != null && tb.next != t)
    return false;
    if (tn != null && tn.prev != t)
    return false;
    if (tp != null && t != tp.left && t != tp.right)
    return false;
    if (tl != null && (tl.parent != t || tl.hash > t.hash))
    return false;
    if (tr != null && (tr.parent != t || tr.hash < t.hash))
    return false;
    if (t.red && tl != null && tl.red && tr != null && tr.red)
    return false;
    if (tl != null && !checkInvariants(tl))
    return false;
    if (tr != null && !checkInvariants(tr))
    return false;
    return true;
    }
    }

    }